Longitudinal research can identify common patterns as well as individual differences in development because the investigator __________.

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: C

Rationale: The blank in the statement refers to an approach that can be used in combination with an experimental strategy. Longitudinal and cross-sectional approaches are two common research methods in developmental psychology. Longitudinal studies involve following the same group of individuals over an extended period, while cross-sectional studies compare different groups of individuals of different ages at the same time. By combining an experimental strategy with either a longitudinal or a cross-sectional approach, researchers can gain a deeper understanding of developmental processes and changes over time. Choices A, B, and D are incorrect because correlational and sequential are not the most relevant approaches when studying developmental changes over time in research.

Correct Answer: D

Rationale: If pregnancy does not occur, the corpus luteum will shrink. As a result, the lining of the uterus is discarded through the process of menstruation. This shedding of the uterine lining is what causes menstrual bleeding. Choices A, B, and C are incorrect because they do not describe the physiological response of the body when pregnancy does not occur. The corpus luteum shrinking and the subsequent shedding of the uterine lining are part of the menstrual cycle, not processes related to cell duplication, zygote multiplication, or the duration of the germinal period.

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.

Correct Answer: B

Rationale: The force of blood flowing through the umbilical cord keeps it firm. The umbilical cord is the connection between the placenta and the fetus, providing essential nutrients and oxygen to the developing baby. Blood flow through the umbilical cord helps maintain its structure and function throughout the prenatal period. Choices A, C, and D are incorrect as they do not play a role in providing nutrients and oxygen to the developing baby or in maintaining its firmness.