At 16 weeks of gestation a pregnant person states, 'The most dangerous time is the first 3 months, so I shouldn’t have to worry from now on about any dangers to the baby.' What is the nurse's most appropriate response?

Correct Answer: A

Rationale: The correct answer is A because teratogens, substances that can harm the developing fetus, can have negative effects on the baby at any point during pregnancy, not just in the first trimester. The nurse's response should educate the pregnant person about the ongoing risks and the importance of avoiding harmful substances throughout pregnancy. Option B is incorrect because an ultrasound is not used to assess the risk of teratogens. Option C is incorrect as it provides incorrect information that the risk is past, which is not true. Option D is incorrect as it is judgmental and does not address the pregnant person's misconception about the risks throughout pregnancy.

Correct Answer: C

Rationale: The correct answer is C: neonatal intensive care. This is because during a home birth, neonatal intensive care is not provided as it requires specialized medical equipment and expertise typically only available in hospitals. Labor support (A) and trained birth attendant (B) are essential for home births. Breastfeeding assistance (D) may be provided post-birth but is not a defining feature of care during a home birth.

Correct Answer: A

Rationale: The correct answer is A: The zona reaction. After fertilization, the zona pellucida undergoes a biochemical change called the zona reaction, which makes the ovum impenetrable to any other sperm. This process prevents polyspermy and ensures that only one sperm can fertilize the egg. Gametogenesis refers to the production of gametes, not the post-fertilization event. The zona pellucida is the glycoprotein layer around the ovum, and cleavage is the rapid mitotic cell division that follows fertilization, but neither of these directly relate to the ovum becoming impenetrable to other sperm.

Correct Answer: C

Rationale: Conjoined twins are formed at about 13 to 15 days after conception when the embryonic disc undergoes incomplete splitting. At this stage, the cells have already differentiated into different layers, making separation challenging. Immediately after fertilization (choice A) is too early for conjoined twins to form. At the time of implantation (choice B) is when the blastocyst implants into the uterine wall, but conjoined twins are not formed at this point. In the blastocyst stage (choice D), the cells are still in the process of organizing and have not yet differentiated into distinct layers. Therefore, choice C is the correct answer as it aligns with the timing of conjoined twin formation during embryonic development.

Correct Answer: C

Rationale: The correct answer is C: Formation of a zygote that contains the diploid number of chromosomes. After fertilization, the sperm and egg combine to form a zygote with a complete set of chromosomes (diploid). This is crucial for genetic diversity and proper development. Choice A is incorrect because a zygote is diploid, not haploid. Choice B is incorrect as an embryo is formed later in development and contains diploid chromosomes. Choice D is incorrect because a morula is a stage where the zygote undergoes several rounds of cell division, but it does not yet contain a full diploid set of chromosomes.