Formation of a retinoblastoma eye tumor requires:

Correct Answer: C

Rationale: Retinoblastoma follows the two-hit hypothesis: a germline mutation in one RB1 allele and a somatic mutation in the other inactivate the tumor suppressor.

Correct Answer: D

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

Correct Answer: D

Rationale: All apply: cancer cells can be transplanted (e.g., in mice), passed to daughter cells (heritable), lose specialization (dedifferentiated), and invade tissues.

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.