The table lists the number of amino acid differences between human cytochrome c and the cytochrome c of four other organisms. Which organism shares the most recent common ancestor with humans?

The table gives the number of amino acid differences between human cytochrome c and the same protein in five other species. Which species is the LEAST closely related to humans?

A study compared a blood protein in five species with the version found in the domestic chicken. The table shows the results. Which species is the chicken's closest relative among those tested?

Use the table of cytochrome c differences from the human protein. Which statement is supported by these data?

A biologist is drawing a cladogram of humans and the four species in the table, using the sequence differences shown. Which species belongs on the branch closest to humans?

A laboratory needs a non-human enzyme that behaves as much like the human enzyme as possible. The table shows how many amino acids each species' version differs from the human one. Which species should the lab choose?

Look at the table of cytochrome c differences from the human protein. Which conclusion is NOT supported by these data?

The table shows how many bases of one gene differ from the human version in four species. Which order lists the species from the most recent separation from the human line to the earliest?

A study compared one gene in four species with the version carried by the domestic cat. Which species separated from the cat's line the earliest?

In the table, the horse and the pigeon have the same number of cytochrome c differences from humans. What does that equal count suggest?

The table shows base differences from a reference species for three species, and differences in this gene build up at a steady rate over time. About how long ago did species C separate from the reference line, compared with species A?

Species W has just been sequenced and added to the table of base differences from the human version of a gene. What does the table best support about species W?

The early embryos of a shark, a turtle, a rabbit and a human all pass through a stage with a post-anal tail and a series of pouches in the neck region, although only the shark keeps those pouches as gill slits. What does this shared stage indicate?

A whale embryo grows a pair of hind limb buds that shrink away before birth, so the adult whale has no hind limbs. What is the best explanation of these buds?

The embryos of a mouse and a bat are hard to tell apart in their earliest stages, and the differences between them appear only later in development. Why do closely related species resemble each other most as early embryos?

Embryos of a lizard and a crocodile stay alike through more developmental stages than either does with a salmon embryo. What does that comparison indicate?

The human gene for insulin was placed into a bacterium, and the bacterium produced working human insulin. What does this result indicate?

Ribosomes read mRNA and build proteins from amino acids in bacteria, in mushrooms and in elephants alike. Which conclusion do these facts best support?

Every organism studied so far uses ATP as the molecule that delivers energy to cellular work, even though other molecules could do the job. A student says this only shows that all organisms need energy. What is the better conclusion?

Cytochrome c is found in bacteria, in fungi, in oak trees and in animals, and it does the same job in the cells of all of them. What does that indicate?