What is one challenge associated with longitudinal research?

Correct Answer: B

Rationale: One challenge associated with longitudinal research is that participants may relocate or drop out of the study over time. This can result in missing data and potential biases in the findings, impacting the study's overall validity and reliability. Furthermore, it can present difficulties for researchers in accurately monitoring and analyzing changes in individuals over an extended period. Options A, C, and D are incorrect because longitudinal research can indeed allow for inferences about cause-and-effect relationships, findings can be generalized to the real world with appropriate design and sampling, and it is suitable for studying individual developmental patterns.

Correct Answer: D

Rationale: Mr. Takashi should be allowed to participate in the study only if it is likely to benefit him directly. This decision aligns with the principle of beneficence in research ethics, which emphasizes maximizing benefits and minimizing risks for research participants. Since Mr. Takashi is incapable of giving consent, his participation should be based on the likelihood of direct benefits to him rather than solely for the benefit of others or solely for research purposes. Option A is too restrictive and does not consider potential benefits to Mr. Takashi. Option B is flawed as it disregards the need for the study to benefit Mr. Takashi. Option C focuses on benefiting others, which is not the primary consideration when the participant cannot give consent.

Correct Answer: C

Rationale: The germinal period lasts about two weeks and occurs during the first two weeks of pregnancy. This is the time when the fertilized egg implants into the uterus and begins to divide rapidly. It is followed by the embryonic period, which lasts from about week 3 to week 8 of pregnancy. Choice A is incorrect because the germinal period happens in the early stages of pregnancy, not the second trimester. Choice B is incorrect because the germinal period typically lasts about two weeks, not six. Choice D is incorrect because the germinal period is an early stage of pregnancy and not the final period of a 38-week pregnancy.

Correct Answer: B

Rationale: The correct answer is B: 'Helps keep the temperature of the prenatal world constant.' Amniotic fluid helps maintain a stable and warm environment for the developing organism, assisting in regulating the temperature. This fluid also acts as a cushion, protecting the fetus from physical harm. Choices A, C, and D are incorrect because while amniotic fluid provides protection and support to the developing organism, it does not directly deliver food, oxygen, nutrients, or remove waste products, nor does it produce blood cells as the organs eventually take over this function.

Correct Answer: B

Rationale: The correct answer is B: nervous system and skin. The nervous system, which includes the brain, spinal cord, and nerves, as well as the skin, develop from the ectoderm layer of cells during prenatal development. Choice A is incorrect because muscles and skeleton develop from mesoderm. Choice C is incorrect because the circulatory system and other internal organs develop from mesoderm and endoderm. Choice D is incorrect because the digestive system, lungs, urinary tract, and glands develop from endoderm.