Correct Answer: A

Rationale: The correct answer is A, gene-environment interaction. This concept highlights that genetic factors play a role in how individuals react to environmental factors. Niche-picking (choice B) refers to the tendency of individuals to select environments that complement their genetic predispositions, not the inherent genetic differences in responsiveness. Passive correlation (choice C) involves the association between the genetic makeup of parents and the environment they provide for their children, not individual differences in responsiveness. Evocative correlation (choice D) relates to the idea that an individual's genetic traits can elicit certain responses from others in the environment, rather than individual differences in responsiveness.

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: A

Rationale: The correct answer is A: 'popular; neglected.' Popular children are well-liked by their peers, hence they receive many positive votes. Neglected children, on the other hand, are often overlooked or ignored, resulting in them being seldom mentioned. Choice B is incorrect because neglected and rejected have different meanings. Choice C is incorrect as popular and rejected do not align with the likability context provided in the question. Choice D is incorrect as controversial does not directly relate to likability in the context of the question.

Correct Answer: B

Rationale: The correct answer is 'Successful.' Successful aging encompasses achieving desirable outcomes and coping effectively with life's challenges and losses. 'Optimal' could imply a focus solely on achieving the best outcomes without considering challenges and losses. 'Peerless' means unmatched or unrivaled, which does not address coping with challenges. 'Capital' is related to wealth or assets and is not suitable in the context of aging and coping with life's difficulties.

Correct Answer: D

Rationale: The correct answer is 'social referencing.' Social referencing is a behavior where infants seek emotional information from a trusted person, usually a caregiver, to determine how to respond in uncertain situations. This process helps infants regulate their emotions and behaviors based on the cues they receive from the trusted individual. Choices A, B, and C are incorrect because self-control, give-and-take, and emotional self-regulation do not specifically involve seeking emotional information from others in uncertain situations, as social referencing does.