Which one of the following refers to one of the 23 chromosome pairs that determines sex in humans?

• A. Autosomes
• B. Mitochondrial DNA
• C. Sex chromosomes
• D. Chromatids

Answer: (C)

In humans, a specific chromosome pair determines sex. There are 23 pairs of chromosomes in most body cells: 22 autosome pairs that carry genes for a wide range of traits, and one pair that determines sex. The sex chromosomes carry the genes that influence sexual development, with typically two X chromosomes in females and one X and one Y in males. The other options describe different genetic content: autosomes are the non-sex chromosome pairs; mitochondrial DNA is a separate genetic material in mitochondria inherited from the mother; chromatids are identical copies of a chromosome formed during replication, not a separate chromosome pair.