In order for one to have a recessive trait (e.g., having red hair), the person must receive?

Correct Answer: B

Rationale: Recessive traits are expressed when an individual inherits two copies of the recessive gene, one from each parent. Therefore, the correct answer is B. Choice A is incorrect as one copy of a recessive gene is not sufficient to display a recessive trait. Choice C is incorrect because having at least one copy of a dominant gene is unrelated to expressing a recessive trait. Choice D is incorrect because two copies of a recessive gene must come from both parents, not just one.

Correct Answer: A

Rationale: Teratogens are substances that can cause birth defects, especially if exposure occurs during critical periods of development. In this context, teratogens refer to external agents that can interfere with the development of the embryo or fetus, leading to structural or functional abnormalities. Choice B, Placenta, is incorrect as it is an organ that develops during pregnancy to provide nutrients and oxygen to the fetus and remove waste products. Choice C, Parturition, refers to the process of giving birth and is not related to substances that cause birth defects. Choice D, Androgens, are male sex hormones and are not associated with causing birth defects.

Correct Answer: A

Rationale: Pruning is the process of eliminating unused synapses in the brain. This process helps the brain to become more efficient by strengthening important connections and eliminating unnecessary ones. Choice B is incorrect because pruning is about eliminating synapses, not developing them. Choice C is incorrect as it refers to the general concept of connections between neurons, not specifically about pruning. Choice D is incorrect as it describes the myelin sheath, which is responsible for rapid transmission of information along neurons, not pruning.

Correct Answer: C

Rationale: The correct answer is C: Secondary circular reactions. Secondary circular reactions are repeated actions that infants engage in to trigger a response from the environment, such as the baby cooing to make the mom smile. This behavior is characterized by a focus on the external environment and the repetition of actions to achieve a desired response. Choices A, B, and D are incorrect. Reflexes (choice A) are automatic, involuntary responses to a stimulus, while primary circular reactions (choice B) involve the repetition of actions primarily for the infant's own enjoyment rather than to elicit a response from the environment. Tertiary circular reactions (choice D) refer to the experimentation with new behaviors and variations in the way the infant interacts with the environment.

Correct Answer: B

Rationale: The correct answer is B. Telegraphic speech is when a child uses a two-word phrase to convey a larger meaning, such as 'mama water.' Choice A is incorrect as it does not demonstrate telegraphic speech but rather a simple labeling. Choice C is incorrect as it is a complete sentence and not a two-word phrase. Choice D is also incorrect as it does not describe telegraphic speech but rather a vague statement about communication.