AP Psychology Practice Test 2025 - Free AP Psychology Practice Questions and Study Guide

Primary sex characteristics refer to the physical features directly involved in reproduction. These include the organs and structures that are essential for the reproduction process itself. In this context, the ovaries, testes, and external genitalia are the primary sex characteristics as they are directly involved in the reproductive system: ovaries produce eggs and hormones in females, while testes produce sperm and hormones in males, and external genitalia allow for mating and reproduction.

In contrast, other choices include secondary sexual characteristics or features that develop during puberty but are not directly tied to the reproductive system. Body hair and voice quality are traits associated with physical maturity but do not play a role in reproduction itself. Breasts and hips, while indicative of female maturation, are also secondary characteristics not essential for reproduction. Height and weight can vary for many reasons and do not specifically correlate to reproductive functions. Thus, the correct answer focuses on those anatomical structures that are fundamental for sexual reproduction.