Correct Answer: A

Rationale: The correct answer is A: Existential. Existentialism is a philosophical perspective that emphasizes individual existence, freedom, and choice. It focuses on finding meaning in life and dealing with fundamental issues such as death. This perspective is characterized by concepts like authenticity, responsibility, and the search for purpose. Choices B, C, and D are incorrect because while they may address certain aspects of human behavior or relationships, they do not specifically emphasize the search for meaning and the confrontation with death as core values.

Correct Answer: C

Rationale: Temperament is the correct answer because it refers to an individual's inborn, relatively permanent trait that distinguishes one person from another. Genotype (choice A) refers to the genetic makeup of an organism, not necessarily a behavioral trait. Phenotype (choice B) is the observable characteristics of an organism resulting from the interaction between its genotype and the environment. Characteristic (choice D) is a broad term that can encompass various traits and features, but it does not specifically denote an inborn and relatively permanent trait that sets individuals apart.

Correct Answer: A

Rationale: The biopsychosocial model is a model that integrates biological, psychological, and social factors. It is important because it recognizes the interconnectedness of these factors in influencing an individual's mental health. Option B is incorrect because the biopsychosocial model does not focus solely on biological factors. Option C is incorrect as the model does not exclude social factors. Option D is incorrect as the model does not focus solely on psychological factors.

Correct Answer: B

Rationale: The correct answer is B because most behaviors are influenced by a complex interaction of many genes and the environment. Choice A is incorrect because it states that it is easy to differentiate between the effects of the environment and genes, which is not the case. Choice C is incorrect because although twin studies are commonly used in genetic research, this alone does not hinder the full understanding of genetic influences on behavior. Choice D is incorrect because even though we have some understanding of how genes impact brain chemistry, this does not mean that we fully understand the genetic influences on behavior.

Correct Answer: A

Rationale: The correct answer is A. Normal human cells have twenty-two chromosome pairs and one pair of sex chromosomes. This adds up to a total of 46 chromosomes. Choice B is incorrect as it mentions twenty-one trisomy chromosome pairs, which is not a characteristic of normal human cells. Choice C is also incorrect as it states twenty-one chromosome pairs and two trisomy chromosome pairs, which is not accurate for normal human cells. Choice D is incorrect as it mentions twenty-three chromosome pairs, which is not the correct number for normal human cells.