Which of the following results in net gain genetic material?

Correct Answer: B

Rationale: Duplication (B) adds genetic material. Rationale: Deletion removes, translocations rearrange (no net gain), while duplication increases gene copies, potentially causing phenotypes like Charcot-Marie-Tooth.

Correct Answer: B

Rationale: MI: homologous chromosomes; MII: sister chromatids (B). Rationale: MI separates homologs, MII splits chromatids, causing aneuploidy if nondisjunction occurs.

Correct Answer: C

Rationale: Amniotic fluid (C) is used in amniocentesis for fetal karyotyping. Rationale: It contains fetal cells (amniocytes) for chromosome analysis; lymphocytes and bone marrow are postnatal, cheek swabs aren’t fetal, and skin biopsy is rare prenatally.

Correct Answer: B

Rationale: Umbilicated lesions (central depression) are characteristic of Molluscum contagiosum (B). Rationale: Pinworms (A) cause pruritus without nodules; lice (C) have nits; Shigella (D) and Streptococcus (E) cause discharge, not umbilicated lesions.

Correct Answer: D

Rationale: Topical estrogens (D) are the standard treatment for labial adhesions. Rationale: Estrogen separates fused labia by promoting epithelial growth; antibiotics (A, B) treat infection, not adhesions; oral estrogens (C) are less targeted.