Final answer:
Humans have 23 pairs of chromosomes in their body cells, of which 22 pairs are autosomes. The remaining pair is the sex chromosomes, differentiating in XX for females and XY for males.
Step-by-step explanation:
Humans have 23 pairs of chromosomes in each of their body cells. Of these pairs, 22 are autosomes, which are chromosomes that contain genes for characteristics that are not related to sex determination. The remaining pair is made up of sex chromosomes, which are either XX in females or XY in males. Therefore, in human body cells, which include somatic cells like skin and muscle cells, there are 22 pairs of autosomes. The autosomes are numbered 1 through 22, with pair 1 being the longest and pair 22 being the shortest. These homologous chromosomes are the same in both males and females. Thus, the correct answer to the question 'How many pairs of autosomes do humans have in their body cells?' is b. 22.