Estrogens, testosterone, cortisol, and aldosterone are all derived from

Correct Answer: B

Rationale: These are steroid hormones synthesized from cholesterol.

Correct Answer: C

Rationale: The pineal gland synthesizes melatonin.

Correct Answer: D

Rationale: Oxytocin is not tropic; it directly affects target tissues.

Correct Answer: D

Rationale: GH increases protein synthesis, not decreases it.

Correct Answer: C

Rationale: Low amino acids do not stimulate GH; low glucose and stress do.