Which of the following are thought to lower the risk of developing cancer?

Correct Answer: D

Rationale: All listed factors reduce cancer risk: smoke and UV are carcinogens; diet impacts risk.

Correct Answer: B

Rationale: Without the pedigree, heterozygous (Aa x Aa) is common for dominant traits with affected and unaffected offspring.

Correct Answer: C

Rationale: X-linked dominant traits show no male-to-male transmission (fathers pass X to daughters only), but ‘transmission only by females’ is inaccurate; males transmit to daughters.

Correct Answer: C

Rationale: Humans have 46 chromosomes in diploid cells (2n=46).

Correct Answer: A

Rationale: Klinefelter (47,XXY) is an aneuploidy, not a chromosome instability syndrome (e.g., DNA repair defects).