In an experiment, the independent variable __________.

Correct Answer: B

Rationale: In an experiment, the independent variable is the one that the investigator expects to cause changes in another variable. It is the factor that is deliberately manipulated or changed by the researcher to observe its effects on the dependent variable. The purpose of manipulating the independent variable is to study its impact on the outcome, allowing researchers to establish cause-and-effect relationships in their investigations. Choice A is incorrect because the independent variable is not influenced but rather influences another variable. Choice C is incorrect as the independent variable is intentionally manipulated by the researcher. Choice D is incorrect as it refers to a different concept unrelated to the independent variable in an experiment.

Correct Answer: A

Rationale: A major strength of the longitudinal design is that researchers can examine relationships between early and later behaviors. This design allows researchers to observe and track changes in the same participants over an extended period of time, providing valuable insights into developmental trajectories and how behaviors are connected across different stages of life. Choice B is incorrect because longitudinal studies track changes over time, not necessarily collect a large amount of data in a short time span. Choice C is incorrect as it refers to cross-sectional studies rather than longitudinal studies. Choice D is incorrect as it describes a cross-sectional design where participants of different ages are studied at the same time.

Correct Answer: C

Rationale: One major disadvantage of cross-sectional research is that factors affecting individual development cannot be explored thoroughly. Cross-sectional research involves comparing different groups of people at one specific point in time, and does not allow for tracking individual changes over time. This limitation means that the unique influences and trajectories of individual development may be overlooked in cross-sectional studies. Choices A, B, and D are incorrect. Choice A is not a major disadvantage of cross-sectional research as age-related changes can still be compared across different groups in this type of study. Choice B, while a potential issue in any study, is not specific to cross-sectional research. Choice D refers to a different type of bias caused by repeated testing rather than a major disadvantage of cross-sectional research.

Correct Answer: D

Rationale: When children are research participants, it is essential to obtain informed consent from their parents or others who act on their behalf. This is to ensure that the child's rights and well-being are protected during the research process. Informed consent is a fundamental ethical principle in research involving children, as they may not have the capacity to fully understand the implications of their participation. Choice A is incorrect because seeking the opinion of others when in doubt about harmful effects is not a substitute for informed consent. Choice B is incorrect because children do not have an absolute right to conceal their identity in research, especially when it comes to ensuring their safety and well-being. Choice C is incorrect as it is important to inform children or their parents about the results of the research to maintain transparency and respect for their participation.