An inborn trait that is relatively permanent and differentiates one person from another is known as ________.

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: Normal human cells have twenty-two chromosome pairs and one pair of sex chromosomes. This is the correct answer as it accurately describes the typical chromosome count in human cells. Choice B is incorrect because it mentions 'twenty-one trisomy chromosome pairs,' which is not characteristic of normal cells. Choice C is incorrect as it suggests having 'two trisomy chromosome pairs,' which is abnormal. Choice D is incorrect as it states 'twenty-three chromosome pairs,' which is not the standard count in normal human cells.

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: B

Rationale: The correct answer is B because most behaviors are influenced by the interaction of multiple genes and the environment. Choice A is incorrect because it suggests that researching the effects of the environment and genes is easy, which is not the case. Choice C is incorrect as it focuses on a specific method (twin studies) rather than the broader concept of gene-environment interaction. Choice D is incorrect as the statement implies a high level of understanding that contradicts the idea that genetic influences on behavior may never be fully understood.

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.