Correct Answer: D

Rationale: The correct answer is D, antigens. Antigens are substances recognized by the immune system as foreign, triggering an immune response to neutralize or destroy them. In this context, T cells and B cells are specialized cells of the immune system that respond to antigens, but they are not the substances being neutralized or destroyed. Telomeres, on the other hand, are protective structures at the end of chromosomes and are not targeted for neutralization or destruction by the immune system.

Correct Answer: C

Rationale: Passionate love is characterized by intense emotions and physical attraction, which are common in the early stages of relationships. Compassionate love involves deep affection, but it develops over time based on mutual respect, trust, and intimacy. Affectionate love is warm and tender, but it may not necessarily have the intense emotions associated with passionate love. Companionate love is based on friendship, respect, and affection, but it may lack the intense emotions and physical attraction that characterize passionate love.

Correct Answer: C

Rationale: The correct answer is C: concrete operational. During the concrete operational stage, children start to engage in logical thinking about concrete events. This stage typically occurs between the ages of 7 to 11 years. Choices A, B, and D are incorrect. The sensorimotor stage (choice A) is the first stage in Piaget's theory, occurring from birth to about 2 years old. The preoperational stage (choice B) follows the sensorimotor stage and occurs roughly from ages 2 to 7 years. The formal operational stage (choice D) is the final stage in Piaget's theory, where abstract thinking and hypothetical reasoning develop, usually beginning around age 11.

Correct Answer: C

Rationale: The correct answer is C: 'competition.' Parents often give boys toys that promote competition and physical activity, aligning with traditional gender roles. This emphasis on competition can help boys develop skills such as leadership, strategy, and resilience. Choice A, 'cooperation,' is incorrect because while cooperation is valuable, it is not typically emphasized through toys given to boys. Choice B, 'nurturance,' is also incorrect as nurturing qualities are not commonly associated with toys given to boys. Choice D, 'physical attractiveness,' is unrelated to the toys parents usually give their sons.

Correct Answer: C

Rationale: In females, the twenty-third pair of chromosomes is indeed labeled as XX. This pair of chromosomes determines the biological sex of females. Choice A, 'an autosome,' is incorrect as autosomes refer to the non-sex chromosomes. Choice B, 'dizygotic,' is incorrect as it relates to twins. Choice D, 'XY,' is incorrect as it represents the chromosome pair found in males.