Correct Answer: C

Rationale: Longitudinal research involves tracking the performance of each person over time. By doing so, researchers can observe common patterns in development among a group of individuals and also identify individual differences in how each person progresses over time. This methodology allows researchers to gather data on the same individuals repeatedly, offering insights into how development unfolds over the lifespan. Choices A, B, and D are incorrect because longitudinal research focuses on observing individuals over time rather than studying groups at a single point, randomly assigning participants to treatments, or conducting quasi-experiments.

Correct Answer: D

Rationale: The correct answer is D. According to the continuous view of development, the difference between the immature and the mature is seen as simply one of amount or complexity. This view suggests that development is a gradual and continuous process where individuals steadily acquire new abilities without abrupt changes or stages. Choices A, B, and C are incorrect because nature, discontinuous, and nurture do not align with the description provided in the question. Nature typically refers to genetic or biological factors, discontinuous implies stages or abrupt changes, and nurture relates to environmental influences, none of which are synonymous with the continuous view of development.

Correct Answer: C

Rationale: To avoid exposure to toxoplasmosis, Kaye should ask other family members to change the litter box. Toxoplasmosis is a parasitic infection that can be transmitted through cat feces, so it is important for pregnant women to avoid handling cat litter to reduce the risk of infection. Choices A, B, and D are incorrect because they are not directly related to preventing toxoplasmosis. Smoking cessation is important for overall health but not specifically to prevent toxoplasmosis. Picking up after the dog and feeding the fish are not relevant to preventing toxoplasmosis, as the infection is primarily associated with cat feces.

Correct Answer: B

Rationale: In a cross-sectional design, researchers study groups of participants differing in age at the same point in time. This design allows researchers to compare different age groups simultaneously, providing valuable insight into age-related differences without the need to track the same group over time. Choice A is incorrect because it describes a longitudinal design where the same group is followed over time. Choice C is incorrect as it involves different groups of the same age studied at different times. Choice D is incorrect as it does not capture the essence of a cross-sectional design, which involves studying groups of different ages at the same point in time.

Correct Answer: C

Rationale: The statement that is true about a blastocyst is that between the seventh and ninth days, it burrows deep into the uterine lining. This process, known as implantation, is essential for the blastocyst to establish a connection with the mother's body and receive nutrients for further development. It is a critical stage in prenatal development and sets the foundation for pregnancy. Choices A, B, and D are incorrect. A blastocyst is not a single cell but rather a structure composed of many cells. It is not a structure that feeds the developing organism; instead, it implants in the uterine lining to receive nutrients. It is not a membrane that regulates temperature but plays a crucial role in the initial stages of pregnancy by implanting in the uterus.