Migration i think is the answer
For centuries, many scientists hypothesized that birds were reptiles due to similarities in their anatomy, but there was no hard fossil evidence to support it. But in 1860, archaeologists discovered a fossil of a highly detailed Archaropteryx lithographica (a bird-like dinosaur), which filled the void of the “transitional species” that scientists needed to link birds and reptiles. Since then, many fossils of feathered dinosaurs have been found.
It would be substitution because an incorrect base pair is being replaced.... hopefully thats right?
I'm pretty sure it's shape and size! If you need more help let me know!
Answer:
Turtles were the first group of animals to branch off in this tree of animals.
Explanation:
Turtles were the first group of animals to branch off in this tree of animals. According to the tree, the animals share a common ancestor. The first branch shows that what we call a speciation event occurred, resulting in two lineages. The first group of animals to result were the turtles. All the other animals are on the other branch. This does not indicate that any group is more highly evolved than the other.