Humans have 23 pairs of chromosomes and chimps have 24 pairs. How has this difference best been explained?
A) Humans and chimps are not related.
B) Chimps gained a chromosome during their evolution, which explains why they differ from humans.
C) Humans and chimps share very little genetic material.
D) Humans have one chromosome that is the result of a fusion of two chromosomes in our ancestors.

Question

Quizplus · Accepted Answer

Humans have one chromosome that is the result of a fusion of two chromosomes in our ancestors, which resulted in a reduction from 24 pairs to 23 pairs. This explains the difference in chromosome number between humans and chimps, who did not undergo this fusion event. Humans and chimps share a significant amount of genetic material and are evolutionarily related.

Humans Have 23 Pairs of Chromosomes and Chimps Have 24