Lanugo ________.

Correct Answer: D

Rationale: Lanugo helps the vernix stick to the skin. Vernix is a waxy substance that covers the fetus's skin during pregnancy. Lanugo is a fine, downy hair that helps to anchor the vernix to the skin, providing protection and nourishment to the developing fetus. Choices A, B, and C are incorrect as they do not accurately describe the role of lanugo in prenatal development.

Correct Answer: A

Rationale: In the germinal period of prenatal development, which lasts for about the first two weeks after fertilization, the developing organism is a zygote that has not yet implanted in the uterus. During this period, teratogens rarely have any impact because essential implantation and early cellular division processes are occurring. Teratogens are more likely to have significant effects during the later embryonic and fetal periods of development. Therefore, the correct answer is A. Choice B, embryonic period, is incorrect because teratogens have a higher likelihood of impacting development during this period. Choice C, fetal period, is also incorrect as teratogens can impact development during this stage as well. Choice D, prenatal, is a broad term encompassing the entire period of development from conception to birth and is not a specific developmental stage where teratogens have a minimal impact.

Correct Answer: A

Rationale: The correct answer is A: 'It is linked to impulsivity and overactivity.' Prenatal marijuana exposure has been associated with impulsivity and overactivity in children based on research findings. However, lasting consequences of prenatal marijuana exposure are not as well-established compared to other teratogens. Choice B is incorrect because lasting consequences are not firmly established. Choice C is incorrect because studies have shown negative effects of prenatal marijuana exposure. Choice D is incorrect as prenatal marijuana exposure is not primarily linked to physical malformations.

Correct Answer: A

Rationale: Recent evidence suggests that paternal alcohol use around the time of conception can alter gene expression. This means that paternal alcohol consumption can potentially impact the genes and genetic materials passed on to offspring, affecting their development and health. Choice B is incorrect because fetal alcohol syndrome is typically associated with maternal alcohol consumption during pregnancy, not paternal alcohol use around conception. Choice C is incorrect as there is no direct link between paternal alcohol use and blood vessel abnormalities. Choice D is incorrect as paternal alcohol use can indeed have negative effects on the developing organism, particularly through altering gene expression.

Correct Answer: C

Rationale: High levels of prenatal lead exposure are related to low birth weight and brain damage. Lead exposure during pregnancy can have harmful effects on the developing fetus, leading to complications such as decreased birth weight and potential long-term brain damage. Choices A, B, and D are incorrect because they do not directly correlate with the known effects of prenatal lead exposure. While lead exposure can indeed cause a variety of health issues, such as heart defects and urinary tract problems, the primary concerns related to prenatal exposure are low birth weight and brain damage.