To overcome some of the limitations of traditional developmental designs, investigators sometimes use __________ designs, in which they conduct several similar cross-sectional or longitudinal studies.

Correct Answer: A

Rationale: Sequential designs involve conducting multiple similar cross-sectional or longitudinal studies to overcome limitations of traditional developmental designs. By combining different types of study designs, researchers can gain a more comprehensive understanding of development over time. This approach allows for more robust conclusions and can help address potential confounding variables that may impact the results.

Correct Answer: D

Rationale: An ovum bursts from one of a woman's two ovaries and is drawn into one of two fallopian tubes. This is a correct description of the process of ovulation and fertilization in human reproductive anatomy. The ovaries are responsible for producing and releasing eggs, while the fallopian tubes provide a pathway for the egg to travel to the uterus for potential fertilization.

Correct Answer: A

Rationale: In the context of pharmacology, understanding embryonic development is crucial as certain drugs can have teratogenic effects during this stage. In this question, the correct answer is A) becomes the new organism. This is because the embryonic disk is a structure formed during embryogenesis that gives rise to the developing organism. It is essential in the formation of the embryo itself. Option B) is the outer ring of cells on a blastocyst is incorrect because the embryonic disk is a distinct structure within the blastocyst that eventually develops into the embryo, not just an outer ring of cells. Option C) has a good chance of survival outside the womb is incorrect as the embryonic disk is not capable of survival on its own outside of the womb at this early stage of development. Option D) is a protective membrane that surrounds the amnion is also incorrect as the embryonic disk is a specific structure within the blastocyst and is not a protective membrane surrounding the amnion. Understanding the developmental stages of an embryo is fundamental in pharmacology to comprehend the potential impacts of drugs on prenatal development. By choosing the correct answer, students demonstrate a grasp of the basic embryonic structures critical to understanding the effects of pharmacological agents on prenatal development.

Correct Answer: C

Rationale: The yolk sac is an extraembryonic membrane that plays a significant role in the early development of the embryo. One of its functions is to produce blood cells until the organs are mature enough to take over this function. This process occurs during the early stages of prenatal development to support the growing embryo before it can sustain itself independently.

Correct Answer: D

Rationale: During the period of the embryo, the endoderm becomes the digestive system, lungs, urinary tract, and glands. The endoderm is one of the primary germ layers that give rise to various internal organs in the developing embryo. It plays a crucial role in the formation of organs such as the digestive system, respiratory system, and glandular structures.