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.

Correct Answer: B

Rationale: The mother feels a natural urge to squeeze and push with her abdominal muscles during the second stage of labor. This stage occurs after the cervix is fully dilated and ends with the delivery of the baby. Choice A (first) is incorrect as the first stage is mainly characterized by the dilation of the cervix. Choice C (third) is incorrect as the third stage is the delivery of the placenta, and choice D (fourth) is incorrect as the fourth stage is the recovery period after childbirth.

Correct Answer: A

Rationale: Dr. Torrez's belief about conflicts between biological drives and social expectations influencing a person's ability to learn, get along with others, and cope with anxiety aligns with the psychoanalytic perspective. This perspective, developed by Sigmund Freud, focuses on the unconscious mind, early childhood experiences, and the resolution of inner conflicts as important factors in shaping personality and behavior. The other choices are incorrect because psychosocial theory, cognitive-developmental theory, and social learning theory do not specifically focus on conflicts between biological drives and social expectations as central to understanding human behavior and development.

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: 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.