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: 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: G. Stanley Hall is generally regarded as the founder of the child study movement. He established the first American research laboratory dedicated to child psychology and education, helping to pioneer the scientific study of child development. Choices A, C, and D are incorrect as they were not primarily associated with founding the child study movement. Charles Darwin is known for his contributions to the theory of evolution, Alfred Binet is famous for developing the first intelligence test, and Sigmund Freud is renowned for his work in psychoanalysis.

Correct Answer: A

Rationale: A rise in the baby's heart rate during pregnancy is usually followed within five seconds by a burst of motor activity. This indicates that the baby is responding to stimuli and is an important sign of healthy fetal development. A period of sleep, a rise in Liz's heart rate, or a drop in Liz's body temperature are not typically immediate responses to changes in the baby's heart rate. Sleep is less likely to be a direct response to changes in heart rate, Liz's heart rate is independent of the baby's heart rate changes, and a drop in Liz's body temperature is not a common immediate response to fetal heart rate changes.

Correct Answer: B

Rationale: Ethnographic research is directed toward understanding a culture through participant observation. This type of observation involves the researcher immersing themselves in the culture being studied, actively participating in the daily activities and interactions of the group being studied. Through participant observation, researchers can gain a deep and nuanced understanding of the culture from the inside. Choice A, naturalistic observation, typically refers to observing subjects in their natural environment without interference, but it does not involve actively participating in the culture. Choice C, systematic observation, focuses on carefully planned and structured data collection methods but may not involve direct participation. Choice D, structured observation, implies a predefined set of guidelines for observation but lacks the immersive aspect of participant observation.