Question

organism | number of amino acid differences from human
chimpanzee | 0
rhesus monkey | 1
rabbit | 9
cow | 10
pigeon | 12
bullfrog | 20
fruit fly | 24
wheat germ | 37
yeast | 42
which organism is most closely related to humans?
options: chimpanzee, rhesus monkey, bullfrog, cow

Explanation:

To determine the organism most closely related to humans, we analyze the number of amino acid differences (from the table). Fewer differences indicate a closer evolutionary relationship. Chimpanzee has 0 differences, which is the lowest among the options (Rhesus Monkey: 1, Bullfrog: 20, Cow: 10). Thus, the chimpanzee is most closely related.

Answer:

chimpanzee