Which statement about human somatic chromosomes is true?

Which statement about human somatic chromosomes is true?

• A. Humans have 50 chromosomes in somatic cells.
• B. Humans have 46 chromosomes in somatic cells.
• C. Humans have 23 chromosomes in somatic cells.
• D. Humans have 60 chromosomes in somatic cells.

Answer: (B)

The key idea is that human somatic (body) cells are diploid, meaning they contain two complete sets of chromosomes. In humans, this is 23 pairs, giving a total of 46 chromosomes in each somatic cell. This is why mitosis preserves the chromosome number from one cell generation to the next: each chromosome is duplicated and then evenly distributed so the daughter cells end up with the full complement. In contrast, gametes (sperm and egg) are haploid and carry only one set of 23 chromosomes, so fertilization restores the diploid number in the offspring.

The key idea is that human somatic (body) cells are diploid, meaning they contain two complete sets of chromosomes. In humans, this is 23 pairs, giving a total of 46 chromosomes in each somatic cell. This is why mitosis preserves the chromosome number from one cell generation to the next: each chromosome is duplicated and then evenly distributed so the daughter cells end up with the full complement. In contrast, gametes (sperm and egg) are haploid and carry only one set of 23 chromosomes, so fertilization restores the diploid number in the offspring.