In the __________ period, teratogens rarely have any impact.

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: 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.

Correct Answer: D

Rationale: In healthy, physically fit women, regular moderate to vigorous exercise during pregnancy is related to improved fetal cardiovascular functioning. Regular exercise has been shown to benefit both the mother and baby by promoting better cardiovascular health and overall well-being during pregnancy. Choices A, B, and C are incorrect as exercise during pregnancy, when done appropriately, does not lead to lower birth weight, higher risk of premature birth, suppressed immune system development, or serious damage to the central nervous system. Instead, it is known to have positive effects on fetal development and maternal health.

Correct Answer: A

Rationale: Having access to social support during stressful periods can greatly reduce the effects of stress on the developing organism. Social support can provide emotional comfort, practical assistance, and a sense of belonging, which can help the expectant mother cope with stress more effectively. This support system can also help mitigate the negative impact of stress on the developing baby during pregnancy. Choices B, C, and D are incorrect because while folic acid is important for prenatal health, it does not directly address the effects of stress. Taking anti-anxiety medication should be done under medical supervision and as a last resort due to potential risks to the developing baby. Bed rest during the last trimester is not a solution to reduce the effects of stress and may not address the underlying causes of stress.