SAT Biology Subject Test Practice Questions

Answer: D, 46. With the exception of germ cells, all human cells have 23 pairs of chromosomes, giving 46 chromosomes in total.

Key Takeaway: Human cells are diploid, meaning they have duplicate copies of each chromosome, with 23 pairs giving rise to 46 total chromosomes. During mitosis, every chromosome pair is copied, so that both daughter cells have a full complement of 46 chromosomes. This is different from meiosis, in which only one of each chromosome in a pair is duplicated, so that the two daughter cells only have 23 chromosomes.