Professor Higgins is concerned about the findings of a longitudinal study on childhood depression that she conducted between 1985 and 2015 in New York because many of the participants witnessed the terrorist attacks on the World Trade Center. Professor Higgins is concerned about __________ effects.

Correct Answer: D

Rationale: The concern Professor Higgins has regarding the findings of the longitudinal study is related to cohort effects. Cohort effects occur when a specific group of individuals experience a common event or circumstance that could influence the results of a study. In this case, the participants witnessing the terrorist attacks on the World Trade Center could have had a significant impact on their development and mental health outcomes, leading to cohort effects observed in the study. Choice A, 'practice,' is incorrect as it refers to the repeated performance of an activity to improve skill. Choice B, 'cross-sectional,' is incorrect as it involves data collection at a single point in time. Choice C, 'dropout,' is incorrect as it refers to participants leaving a study prematurely.

Correct Answer: B

Rationale: Ethical standards permit deception in research studies if investigators satisfy institutional review boards that such practices are necessary. Institutional review boards are responsible for ensuring that research studies comply with ethical guidelines and protect the welfare of study participants. Deception should only be used when necessary, and the board's approval indicates that safeguards are in place to minimize harm to participants. Choices A, C, and D are incorrect because ethical deception in research studies is not based on the age of participants, observing from behind mirrors, or obtaining informed consent without revealing the study's real purpose.

Correct Answer: B

Rationale: The correct answer is B. The corpus luteum is a temporary endocrine structure in the ovary that forms after ovulation. It secretes hormones, particularly progesterone, which help prepare the uterine lining for possible implantation of a fertilized ovum. This process is crucial for maintaining a potential pregnancy. Choices A, C, and D are incorrect. Choice A is inaccurate as fertilization typically occurs in the fallopian tubes. Choice C describes the fallopian tubes, not the corpus luteum. Choice D refers to the ovaries, not specifically the corpus luteum.

Correct Answer: B

Rationale: During the first week of pregnancy, the zygote (fertilized egg) undergoes rapid cell divisions and forms a blastocyst. This is a crucial stage where the cells differentiate and specialize, setting the foundation for the development of the embryo. It is during this time that the zygote implants itself into the uterine wall, initiating the process of pregnancy. Choices A, C, and D are incorrect because during the first week of pregnancy, the focus is on the initial development and multiplication of the zygote, not on the development of heart muscles, a primitive brain and spinal cord, or the embryo's ability to move.

Correct Answer: D

Rationale: The placenta delivers food and oxygen to the developing organism during pregnancy. It is a temporary organ that forms in the first trimester of pregnancy. Choice A is incorrect as the placenta forms in the first trimester, not the second trimester. Choice B is incorrect as the amniotic sac, not the placenta, encloses the developing organism in amniotic fluid. Choice C is incorrect as the placenta contains blood vessels (arteries and veins) that deliver nutrients to the embryo, not just one large vein.