Question

Cytochrome c is a protein that is found in the mitochondria of all aerobic eukaryotic cells. The gene sequence for cytochrome c has been mapped and analyzed for thousands of species. The table shows the percentage of the cytochrome c amino-acid sequence that different species have in common.

Percent Similarity of Cytochrome c Amino-Acid Sequence
Chimpanzee; Horse; Donkey; Mouse; Lamprey;. Chimpanzee; Horse; Donkey; Mouse; Lamprey.

Which list is ordered from the species most closely related to the mouse to the species least closely related to the mouse?

A
Horse, chimpanzee, donkey, lamprey
B
Lamprey, donkey, chimpanzee, horse
C
Chimpanzee, donkey, lamprey, horse
D
Donkey, horse, chimpanzee, lamprey

Answer 1

I don't have the actual percent-similarity numbers from the table you mentioned — the problem text you pasted looks garbled. Could you re-post the table (or the percent-similarity values between mouse and each species)?

Based on evolutionary relationships (and cytochrome c similarity usually reflecting that), the expected order from most to least closely related to mouse is:
1) chimpanzee (another placental mammal, primate),
2) horse and donkey (other placental mammals—equids—about equally related),
3) lamprey (a jawless fish, the most distant).

If you send the table values I will pick the correct multiple-choice letter and show the comparison.