Accurate Chromosome Statements in Human Cells

Steps:

• Statement 1 is incorrect: Not all human body cells contain 46 chromosomes, as mature red blood cells lack a nucleus and thus have none.
• Statement 2 is incorrect: Gametes contain 23 unpaired chromosomes, not pairs.
• Statement 3 is correct: Males possess one X and one Y chromosome in each somatic body cell.
• Statement 4 is correct: Each chromosome consists of a single long DNA molecule segmented into genes.
• Statement 5 is incorrect: Genes are segments of the DNA molecule, not the reverse.

Why D is correct:

• Statements 3 and 4 align with genetic definitions: males are XY in diploid cells, and chromosomes are DNA organized into functional gene units.

Why the others are wrong:

• A: Includes statement 2, which misstates gamete chromosome pairing.
• B: Includes statement 1, which overlooks chromosome absence in some body cells like erythrocytes.
• C: Includes statements 2 and 5, both of which reverse or misdescribe chromosome and gene structure.

Final answer: D