Your Inner Fish: A Journey Into the 3.5 Billion-Year History of the Human Body is a book discussing the history of the human body and its similarities to other organisms, published in 2008 and written by Neil Shubin, a paleontologist and professor. Your Inner Fish is a remarkable book that never fails to inform and entertain the audience, for it discusses evolution in a way that is both concise and accessible.
Shubin begins the book by stating that he spends a large amount of his time trying to uncover fish bones, for knowing the anatomy of fish provides various insights into the human body. That is, “Ancient fish bones can be a path to knowledge about who we are and how we got that way. We learn about our own bodies in seemingly bizarre places, ranging from the fossils of worms and fish recovered from rocks from around the world to the DNA in virtually every animal alive on earth today” (3). Shubin then states that more than 99% of all species on Earth have gone extinct, and most of them aren’t preserved as fossils, which makes trying to piece together a comprehensive history difficult, to say the least. He then states that paleontologists as a whole plan to find fossils while knowing that their plans can be an utter debacle, for there is no sure way as of yet to locate fossils. Shubin then speaks of how fish migrated to land hundreds of millions of years ago, and that his research showed “one of the great transitions in the history of life: the invasion of land by fish. For billions of years, all life lived only in water. Then, as of about 365 million years ago, creatures also inhabited land. Life in these two environments is radically different. Breathing in water requires very different organs than breathing in air. The same is true for excretion, feeding, and moving about. A whole new kind of body had to arise” (5-6). Shubin then writes that even though the migration of fish to land is very hard to imagine, what may seem impossible can occur after large geographic intervals. Furthermore, Shubin writes that even though it is a reasonable assumption to believe that layers of rocks deep in the ground are older than layers closer to the top, in some instances this can be inaccurate due to earthquakes and other phenomena. Despite this, the geography is quite revealing, for “If we could quarry a single column of rock that contained the entire history of life, we would find an extraordinary range of fossils. The lowest layers would contain little visible evidence of life. Layers above them would contain impressions of a diverse set of jellyfish-like things. Layers still higher would have creatures with skeletons, appendages, and various organs, such as eyes. Above those would be layers with the first animals to have backbones … Of course, a single column containing the entirety of earth history does not exist. Rather, the rocks in each location on earth represent only a small sliver of time” (6-7).
Shubin then writes that since his job relied on rocks that are 375-80 million years old, the best place to find them would be areas with wide spaces to move around which also include bedrock. Shubin provides a list of how to design a successful fossil expedition: “find rocks that are of the right age, of the right type (sedimentary), and well exposed … Ideal fossil-hunting sites have little soil cover and little vegetation, and have been subject to few human disturbances” (12). Shubin then writes that he went to the Arctic with his colleagues to find fossils and that it took them years to make their discovery; for two summers, the fish Shubin and his team uncovered had already been discovered and were too far back in evolutionary history to provide much insight about the movement of fish to land. Over four days in July 2004, however, everything changed: Shubin and his team unearthed a fish with a flat head. In his own words, “We were looking at the front end, and with luck the rest of the skeleton might be safely sitting in the cliff. Steve spent the rest of the summer removing rock from it bit by bit so that we could bring the entire skeleton back to the lab and clean it up” (22). The fish that was found was indeed a new one, for it was a cross between a fish and an animal: “Like a fish, it has scales on its back and fins with fin webbing. But, like early land-living animals, it has a flat head and a neck. And, when we look inside the fin, we see bones that correspond to the upper arm, the forearm, even parts of the wrist. The joints are there, too: this is a fish with shoulder, elbow, and wrist joints. All inside a fin with webbing” (23). Shubin writes of how glad he was with his team to discover it, for it more than paid off for the costs associated with his expedition, not to mention that it was found in the right environment: it was found in 375-million-year-old rocks which were once at the bottom of a river or stream. Shubin and his team decided to consult the locals for the name of the creature, and the native Inuits stated that it should be called the “Tiktaalik,” which translates to “large freshwater fish.” The Tiktaalik generated a large amount of excitement in the scientific community and received a substantial amount of media coverage, and Shubin writes that when he visited the preschool his son went into, even the preschoolers could see that it was a cross between a fish and a land animal like the crocodile or the lizard. Shubin writes that the Tiktaalik reflects the anatomy of humans and other animals, for it was the first fish to have a head that could move around. Furthermore, the bones of the wrist of the Tiktaalik could still be found today, albeit in a much-changed form, in humans (as seen in the bones of our arms).
Shubin then writes of human anatomy, and that the human body is intricate and wondrous: the human hand, of course, has the thumb. Shubin states that the ball of your thumb (otherwise known as the “thenar eminence”) contains four muscles. “Twiddle your thumb and tilt your hand: ten different muscles and at least six different bones work in unison. Inside the wrist are at least eight small bones that move against one another … Even the simplest motion involves a complex interplay among many parts packed in a small space” (29). Shubin then writes of the Scottish doctor Sir Charles Bell who wrote The Hand, Its Mechanism and Vital Endowments as Evincing Design, in which he described how amazing the hand was and that it was probably created by a divine being, seeing how well it worked for humans. Later on, the anatomist Sir Richard Owen studied a vast amount of animals, and he found that living organisms shared many similarities when it came to their fundamental structure, even though their bodies obviously differed. That is, the architecture of limbs can be described as follows: “All creatures with limbs, whether those limbs are wings, flippers, or hands, have a common design. One bone, the humerus in the arm or the femur in the leg, articulates with two bones, which attach to a series of small blobs, which connect with the fingers or toes” (30). Shubin proceeds to describe that the main difference between various organisms are the shapes and sizes of their bones and the number of fingers, toes, and blobs which they possess. To reiterate, though organisms come in great diversity, their underlying structure and functioning are the same. Owen, upon making his observation, also attributed the similarities to a divine being, seen in his publication On the Nature of Limbs. Charles Darwin, however, largely disposed of the need for a divine creator by brilliantly coming up with the theory of natural selection: the main reason various animals have the same structure is that they had a common ancestor.
Shubin then discusses his own experience once more, explaining that before the discovery of the Tiktaalik, his team was eager to find the remains of a fish which possessed a wrist. They eventually found one, and upon analyzing the fossils, saw that the hand of said fish was both a fin and a limb. He goes back to the Tiktaalik, writing that it “has a shoulder, elbow, and wrist composed of the same bones as an upper arm, forearm, and wrist in a human. When we study the structure … we see that Tiktaalik was specialized for a rather extraordinary function: it was capable of doing push-ups” (39). Shubin then discusses that push-ups require hands, elbows, and chest muscles, all of which require the Tiktaalik to have attributes akin to the animals of today. The Tiktaalik did indeed have them, for its elbow and wrists could bend, and it had a significant amount of chest strength, seen in its pectoral muscles. Shubin writes that being able to do push-ups is an evolutionary advantage, for the Tiktaalik, “With a flat head, eyes on top, and ribs,” survived by staying at the bottom of streams and ponds, which required it to be able to move on various rock layers and uneven surfaces. Shubin writes that the reason fish moved to land was because of an abundance of predators which could be up to sixteen feet long: Shubin elucidates that “It is no exaggeration to say that this was a fish-eat-fish world” (41). Shubin then connects this back to humans, writing that “The first bits of our upper arm and leg are in 380-million-year-old fish like Eusthenopteron. Tiktaalik reveals the early stages in the evolution of our wrist, palm, and finger area. The first true fingers and toes are seen in 365-million-year-old amphibians like Aconthostega. Finally, the full complement of wrist and ankle bones found in a human hand or foot is seen in reptiles more than 250 million years old. The basic skeleton of our hands and feet emerged over hundreds of millions of years, first in fish and later in amphibians and reptiles” (42). Shubin writes that many of humanity’s remarkable abilities, like being a bipedal mammal and having capable and inventive hands, stemmed from basic processes, clearly showing that reality is quite remarkable, giving credence to the quote “reality is stranger than fiction.”
Shubin describes the development of arms during gestation, mentioning that limbs begin as little buds that are hardly noticeable. Over the weeks, they develop and grow. Shubin details that in the 1950s and 1960s, biologists like Edgar Zwilling and John Saunders were able to add a large amount of knowledge to science by changing the physiology of animals that were developing. That is, “They discovered that two little patches of tissue essentially control the development of the pattern of bones inside limbs. A strip of tissue at the extreme end of the limb bud is essential for all limb development. Remove it, and development stops. Remove it early, and we are left with only an upper arm, or a piece of an arm. Remove it slightly later, and we end up with an upper arm and a forearm. Remove it even later, and the arm is almost complete, except that the digits are short and deformed” (49). Later on, another experiment involved transporting a piece of tissue “from what will become the pinky side of the limb bud” to another part of the body of the chicken: what resulted was that the chicken “had a full duplicate set of digits” which “were mirror images of the normal set” (49). Shubin then writes of DNA, reminding the audience once again of the great similarities between various living organisms. Shubin discusses teeth, writing that the job of teeth is to obviously turn large chunks of food into manageable parts to provide the said organism with sustenance. Shubin writes that an organism’s teeth reveal quite a large amount of information of the organism, for carnivores have sharp teeth while herbivores generally have flat ones. Humans, of course, are omnivores, hence why we have relatively sharp teeth at the front and flat molars at the back. In Shubin’s own words, “Our front teeth, the incisors, are flat blades specialized for cutting. The rearmost teeth, the molars, are flatter, with a distinctive pattern that can macerate plant or animal tissue. The premolars, in between, are intermediate in function between incisors and molars” (61). Shubin states that teeth are the hardest parts of various bodies, for they are mandatory for survival. Consequently, teeth are the most frequent parts of organisms to be fossilized, which is a great boon for paleontology. Shubin writes that reptiles replace their teeth throughout their entire lives, while humans keep a set of permanent teeth. He discusses his personal experiences as a paleontologist, describing various strategies paleontologists use to maximize their chances of finding fossils: one of the best is for the paleontologist to separate themselves from their colleagues, thereby giving each person their own plot of land to investigate.
Shubin writes again of teeth and discusses bones alongside them. He describes that teeth are composed of hydroxyapatite, which “impregnates the molecular and cellular infrastructure of both teeth and bones, making them resistant to bending, compression, and other stresses. Teeth are extra hard because their outer layer, enamel, is far richer in hydroxyapatite than any other structure in the body, including bone. Enamel gives teeth their white sheen” (74). Shubin states that other organisms like lobsters and clams may not use hydroxyapatite for the hard parts of their bodies: instead, they use chitin and calcium carbonate. Shubin introduces conodonts, “small shelly organisms with a series of spikes projecting out of them” - these organisms lived from 500 to 250 million years ago. Shubin then talks about ostracoderms, which are fish with a bony surface covering their head. Shubin describes that if you cut the skull of an ostracoderm, you will find that you will find “the same structure as in our teeth. There is a layer of enamel and even a layer of pulp. The whole shield is made up of thousands of small teeth fused together. This bony skull … is made entirely of little teeth. Teeth originally arose to bite creatures; later, a version of teeth was used in a new way to protect them” (78). Shubin moves on to discuss the human skull, stating that the cranium is made up of plates, blocks, and rods. Plates are supposed to protect the brain by covering them. It is interesting to note that the plates for the skulls of infants have not come together, for the plates are separate when people are born. Blocks “have many arteries and nerves running through them” while rods compose “our jaws, some bones in our ears, and other bones in our throats; these bones start development looking like rods, which ultimately break up and change shape to help us chew, swallow, and hear” (83). Shubin states that four nerves have challenged medical students for many years: among them, the most challenging ones are the trigeminal branch and the facial nerve. The trigeminal branch controls muscles and transports sensory information from the face to the brain, meaning that this nerve also helps people chew food. The facial nerve, as its name suggests, “is the main nerve that controls the muscles of facial expression. We use these tiny muscles to smile, to frown, to raise and lower our eyebrows, to flare our nostrils, and so on” (85).
Shubin eventually elaborates on embryonic development once again, writing that when humans are developing, our “gill region” is akin to that of a sharp at the beginning of gestation, seeing that both embryos have four arches which later develop into various organs. The first arch develops into jaws for both sharks and humans, and also gives humans ear bones. The second arch turns into structures at the bottom of the head and throat for humans, while it changes into two bones which support the jaws for sharks. The third and fourth arches develop into muscles that allow people to swallow and talk, while sharks are able to have their functioning gills thanks to them. Shubin states that “There is a pattern common to every skull on earth, whether it belongs to a shark, a bony fish, a salamander, or a human” (93). This is reinforced by an image that he attached on page 92 which showed that the various nerves of the human brain are also found in sharks. Shubin discusses the Amphioxus, a worm with gills. While it appears to be largely headless, it indeed has the basic structure of a head. The human body has two trillion cells, all of which once came from a sperm and egg. Shubin details research on gestation, stating that when chicken embryos were studied, it was realized that all their organs can be linked to one of three layers of tissue. This phenomenon is applicable to all animals, and Shubin writes of embryonic development. In his own words, “At the moment of fertilization, major changes happen inside the egg-the genetic material of the sperm and egg fuses and the egg begins to divide. Ultimately, the cells form a ball. In humans, over about five days … a ball of sixteen cells … known as a blastocyst, resembles a fluid-filled balloon … On about the sixth day after conception, the ball of cells attaches to its mother’s uterus and begins the process of connecting to it so that mother and embryo can join bloodstreams. There is still no evidence of the body plan. It is a far cry from this ball of cells to anything that you’d recognize as any mammal, reptile, or fish, much less a human” (100). Later on, however, as the cells multiply, “we become a tube with a folded swelling at the head end and another at the tail. If we were to cut ourselves in half right about now, we would find a tube within a tube. The other tube would be our body wall, the inner tube our eventual digestive tract. A space, the future body cavity, separates the two tubes … The gut tube gets more complicated, with a big sack for a stomach and long intestinal twists and turns. The outer tube is complicated by hair, skin, ribs, and limbs that push out” (101). Shubin writes that the outer layer is known as the ectoderm, the inner layer is nicknamed the endoderm, and the middle layer is recognized as the mesoderm. The ectoderm, as stated before, composes the outer part of the body, including the skin and the nervous system. The endoderm forms the inside layer and includes the digestive tract and various glands. The mesoderm, the middle layer, forms organs in between the digestive tract and the skin, including the skeleton and various muscles. Shubin states that “Whether the body belongs to a salmon, a chicken, a frog, or a mouse, all of its organs are formed by endoderm, ectoderm, and mesoderm” (102). Furthermore, the distinguishing features of organisms don’t arise until later in development.
Shubin then writes of the similarities between humans and sea anemones: they both have a front end, central region, and back end. Shubin moves on to discuss organs, writing that they are composed of masses of cells that specialize at certain tasks. Shubin then discusses cancer, writing that “When the finely tuned balance among the different parts of bodies breaks down, the individual creature can die. A cancerous tumor, for example, is born when one batch of cells no longer cooperates with others. By dividing endlessly, or by failing to die properly, these cells can destroy the necessary balance that makes a living individual person. Cancers break the rules that allow cells to cooperate with one another. Like bullies who break down highly cooperative societies, cancers behave in their own best interest until they kill their larger community, the human body” (118-9). Shubin then states that if Earth’s 4.5 billion-year history was to be compiled into a single year, “Until June, the only organisms were single-celled microbes, such as algae, bacteria, and amoebae. The first animal with a head did not appear until October. The first human appears on December 31. We, like all the animals and plants that have ever lived, are recent crashers at the party of life on earth” (119-20). Shubin states that rocks that are older than 600 million years generally have no bodies encased in them as seen in animals and plants: they only contain single-celled organisms and algae. Shubin states that skeletons evolved so that animals can move on land, and that they are wonders of nature: “The cells are highly organized in places, particularly on the outer rim of the bone. Some cells stick together, whereas others are separated. Between the separated cells are the materials that define the strength of bone. One of them is the rock, or crystal, known as hydroxyapatite … Hydroxyapatite is hard the way concrete is: strong when compressed, less strong if twisted or bent. So, like a building made of bricks or concrete, bones are shaped so as to maximize their compressive functions and minimize twisting and bending, something Galileo recognized in the seventeenth century” (125). Shubin then discusses collagen, the most common protein present in the human body. When greatly magnified, collagen appears as a rope composed of bundles of molecular fibers. Collagen, “like rope, is strong when pulled but weak when the ends are pushed together” (125). Cartilage is a material that appears at the joints, and its sole purpose is to work as a cushion. The reason cartilage is pliable is that the cells present in it have a lot of space between them. Furthermore, collagen is present in cartilage, and the proteoglycan complex also exists in cartilage. As Shubin describes, “Shaped like a giant three-dimensional brush, with a long stem and lots of little branches, the proteoglycan complex is actually visible under a microscope. It has an amazing property relevant to our abilities to walk and move, thanks to the fact that the tiniest branches love to attach to water. A proteoglycan, then … swells up with water, filling up until it’s like a giant piece of Jell-O. Take this piece of gelatin, wrap collagen ropes in and around it, and you end up with a substance that is both pliant and somewhat resistant to tension … A perfect pad for our joints” (127).
Placozoans are organisms with only four types of cells which appear as plates. Though they are very small, their bodies do exhibit division of labor. Also, choanoflagellates are organisms that are akin to animals. Shubin then writes of the human nose, and that other animals also have them, though they do vary: “Fish like lungfish or Tiktaalik have two kinds of nostrils: an external one and an internal one … Air enters an external nostril and travels through your nasal cavities to enter the back of your throat via internal passageways” (143). 3% of the genes of Homo Sapiens are allocated to smell, yet hundreds of them are inactive due to evolution and mutations. In Shubin’s own words, “We carry a lot of baggage in our noses-or, more precisely, in the DNA that controls our sense of smell. Our hundreds of useless olfactory genes are left over from mammal ancestors who relied more heavily on the sense of smell to survive … That baggage is a silent witness to our past; inside our noses is a veritable tree of life” (147). The human eye, like every other organ, is complex, using a variety of subparts to operate properly. Opsins are the molecules used by animals to capture light. Furthermore, when experiments were done on developing fly embryos that involved their eyes, it was found that a single gene, Pax 6, was responsible for the development of vision. The ear is made up of three parts in humans: the outer ear, the middle ear, and the inner ear. The outer ear is the channel that leads from the exterior of the ear to its inner machinery. The middle ear is composed of three important bones: the malleus, incus, and stapes. Shubin then reveals that these three bones appear as gill arches in fish on a graphic on page 163, and that the malleus and incus evolved from jawbones while the stapes is an arch bone. That is, “The stapes … is the corresponding bone in a shark and a fish-the hyomandibula … In our aquatic cousins, this bone is a large rod that connects the upper jaw to the braincase” (162). As for the inner ear, we can find tubes and sacs filled with gel. The cochlea is shaped like a snail, and it contains fluids that help people with their sense of balance. “The inner ear has different parts dedicated to different functions. One part is used in hearing, another in telling us which way our head is tilted, and still another in recording how fast our head is accelerating or stopping … The several parts of the inner ear are filled with a gel that can move. Specialized cells send hairlike projections into this gel. When the gel moves, the hairs on the ends of … these cells bend. When these hairs bend, the nerve cells send an electrical impulse to the brain, where it is recorded as sound, position, or acceleration” (164-5).
The reason alcohol frequently causes people to move unevenly and to have little to no sense of balance is that it introduces ethanol into the bloodstream, which decreases a person’s inhibitions. As a quote described from The Simpsons, “Alcohol only makes you do what you want to do.” Furthermore, a while after drinking, the ethanol from alcohol diffuses in the fluid of the inner ear, which causes the density of the gel to decrease. Consequently, the hairlike projections are much more likely to be stimulated, which causes people to lose their sense of balance: “This change in density wreaks havoc on the intemperate among us. Our hair cells are stimulated and our brain thinks we are moving. But we are not moving; we are slumped in a corner or hunched on a barstool. Our brain has been tricked” (168). During a hangover, the liver removes ethanol from the blood, causing the density of the fluids in the ears to change yet again, bringing back difficulties in balance. Shubin moves on to write that our inner ear actually contains the skin of fish - neuromasts. Neuromasts are frequently found in various places on fish (to help the fish realize the direction water is flowing). Shubin speaks from a large perspective once again, writing that humans are very similar to other animals. He provides the audience with a list of statistics: “The oldest many-celled fossil is over 600 million years old. The earliest fossil with a three-boned middle ear is less than 200 million years old. The oldest fossil with a bipedal gait is around 4 million years old” (184). He then echoes Carl Sagan’s quote that stars are time capsules (every light-year the star away shows the star the same amount of years back in time - a star forty million light-years away is seen by a spectator on Earth as it was forty million years ago, not as it is in the present) by saying that “looking at humans is much like peering at the stars. If you know how to look, our body becomes a time capsule that, when opened, tells of critical moments in the history of our planet and of a distant past in ancient oceans, streams, and forests … The environment of ancient streams shaped the basic anatomy of our limbs. Our color vision and sense of smell have been molded by life in ancient forests and plains” (184).
Shubin then writes that the reason many animals are susceptible to disease and various injuries, both petty and lethal, is that although bodies do offer advantages to the collection of cells, they do have limitations. He describes in detail that Homo Sapiens is similar to the Volkswagen Beetle: Dr. Ferdinand Porsche was commissioned by Adolf Hitler in 1933 to create an affordable car that could travel 40 miles per gallon of gasoline. Shubin writes that trying to make the car capable of travelling 150 miles per hour is highly infeasible, a task which is comparable to trying to make humans biologically perfect, without flaw. As he writes, “Take the body plan of a fish, dress it up to be a mammal, then tweak and twist that mammal until it walks on two legs, talks, thinks, and has superfine control of its fingers-and you have a recipe for problems. We can dress up a fish only so much without paying a price. In a perfectly designed world-one with no history-we would not have to suffer everything from hemorrhoids to cancer … Follow some nerves and you’ll find that they make strange loops around other organs, apparently going in one direction only to twist and end up in an unexpected place. The detours … often create problems for us-hiccups and hernias, for example” (185-6). Shubin then writes that some of the most common causes of death - obesity (leading to the other three on this list), diabetes, heart disease, and strokes - have directly occurred because humans were made by evolution to move around. However, our current lifestyle is largely sedentary, and some people eat very unhealthy foods high on calories and sugar while exercising very little, which directly leads to poor health. A scientist, James Neel, came up with the “thrifty genotype” hypothesis which states that the reason people have the ability to become fat in the first place was that our ancestors as hunter-gatherers may go long periods of time without food (ex. winters), so that their bodies had to be able to store some fuel for hard times. However, in the present, fat is frequently unused and is kept for long periods of time, causing health problems and potential death: “Obesity and its associated maladies … become the natural state of affairs. The thrifty genotype hypothesis also might explain why we love fatty foods. They are high-value in terms of how much energy they contain, something that would have conferred a distinct advantage in our distant past” (187-8). In another instance, people who may work desk jobs and those who drive trucks frequently develop hemorrhoids because the veins of legs are supposed to be frequently used, not neglected: “The one-way valves and the leg-muscle pumps enable our blood to climb from feet to chest. This system works superbly in an active animal … It does not work well in a more sedentary creature. If the legs are not used much, the muscles will not pump the blood up the veins. Problems can develop in blood pools in the veins because that pooling can cause the valves to fail. This is exactly what happens with varicose veins. As the valves fail, blood pools in the veins. The veins get bigger and bigger, swelling and taking tortuous paths in our legs” (188).
Shubin then states that the privilege to talk comes at the price of choking and sleep apnea. Shubin writes that people hiccup because of a nerve which we share with fish. In his own words, “It turns out that the pattern generator responsible for hiccups is virtually identical to one in amphibians. And not in just any amphibians-in tadpoles, which use both lungs and gills to breathe … The parallels between our hiccups and gill breathing in tadpoles are so extensive that many have proposed that the two phenomena are one and the same” (192). Shubin then ends his book by stating that science is an inspirational field, for it discovers and invents what many may consider implausible or even ridiculous. He details inspiringly that “As we learn more, what once seemed distant and unattainable comes within our comprehension and our grasp. We live in an age of discovery, when science is revealing the inner workings of creatures … Looking back through billions of years of change, everything innovative or apparently unique in the history of life is really just old stuff that has been recycled, recombined, repurposed, or otherwise modified for new uses. This is the story of every part of us, from our sense organs to our heads, indeed our entire body plan” (201).
Personal thoughts:
Your Inner Fish is an informative, powerful, and thought-provoking read by the scientist Neil Shubin. It effectively details similarities between humans and other animals, not just fish, which clearly defines one of the core tenets of evolution: humans are not more “evolved” than other animals, for evolution has no end product in mind. Your Inner Fish is also effective due to it being able to classify humanity in the big picture, seen best in the compression of 4.5 billion years of history into a single one. One of the major lessons from Your Inner Fish is that all living organisms are interconnected, clearly illustrating the sheer complexity of biology on Earth. I highly recommend Your Inner Fish: A Journey Into the 3.5 Billion-Year History of the Human Body to anyone interested in biology, discoveries, anatomy, and research.
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