Correct Answer: A

Rationale: During adolescence, individuals start to rely more on feedback from close friends to develop their self-concept. Close friends play a significant role during this transitional period as they provide peer validation, support, and influence. Family members, although important, may not hold the same level of influence on self-concept during adolescence as close friends do. Younger children are unlikely to provide the necessary feedback and validation needed during this developmental stage. While self-reflection and understanding the inner self are vital for personal growth, during adolescence, external feedback from close friends tends to have a more pronounced impact on shaping self-concept.

Correct Answer: A

Rationale: The correct answer is A: fluid. Fluid intelligence, which involves problem-solving and reasoning, tends to decline earlier than crystallized intelligence. Crystallized intelligence, on the other hand, involves knowledge and skills acquired over time and is more stable with age. Emotional intelligence and cultural intelligence are not directly related to the decline of mental abilities mentioned in the question, making them incorrect choices.

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: D

Rationale: The formal operational stage in Piaget's theory is characterized by abstract reasoning, hypothetical thinking, and logical reasoning. This stage represents the most complex period of cognitive development according to Piaget. Choices A, B, and C refer to earlier stages in Piaget's theory and do not involve the level of abstract thinking and logical reasoning seen in the formal operational stage.

Correct Answer: D

Rationale: Heaven is a preterm infant because she was born early, but her weight is appropriate for the time she spent in the womb. Choice A, 'small-for-date,' is incorrect as it does not specifically indicate that the infant was born before the due date. Choice B, 'small-for-weight,' is incorrect because the infant's weight is appropriate for the gestational age. Choice C, 'mature,' is incorrect as it does not reflect the early birth of the infant.