My attempt at an explanation
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Ducks are dinosaurs: Ducks, as with all birds, evolved from theropods and are considered living dinosaurs.
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Horses walk on middle fingers: Ancestors of modern horses have 5 toes the size of a small dog. Eventually they evolved away the other toes and only the middle toe remain.
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Bees are crustaceans: Crustacea is not a single branch in the tree of life but a collection of multiple branches (i.e. paraphyletic). If we pick a point and said everything after that is considered the same group, then by necessity we have to put bees (and all hexapoda) and what we traditionally call crustaceans into a single group. That group would be pancrustacea. Is that exactly the same as saying bees are crustaceans? Are jackdaws crows? I'll let you decide.
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Pterodactyls are fish: Fish is also not a single branch. By the same token, if we want to put what we traditionally counted as fish (such as sharks, carps, and lungfishes) together as a single group, we have to include all vertebrates (which includes pterodactyls, us, whales, etc.)
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Redwood are algae: I'm not too sure about this one. The wikipedia page for algae say that it excludes the land plants (embryophytes) which redwoods are part of.
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Humans are part virus: Viruses have the ability inject and splice their genetic material into our genome and have our cells do the cloning for them. Usually it is not passed on to the next generation. Apparently an ancient strain of virus from millions of years ago incorporated themselves into our genome and our germ cells (sperm and egg) and can be passed on to the next generation.
