Correct Answer: C

Rationale: Genetics is the branch of biology that focuses on the study of heredity and variation in organisms. Etiology (choice A) deals with the causes of diseases, not heredity. Ecology (choice B) is concerned with the relationships between organisms and their environment, not specifically heredity. Eugenics (choice D) is a controversial field that involves improving the genetic quality of the human population through selective breeding, which is different from the study of heredity itself.

Correct Answer: A

Rationale: A fetal heart rate of 60 beats per minute is significantly below the normal range (110-160 bpm) and indicates fetal distress, requiring immediate intervention. This low heart rate can be a sign of fetal compromise or distress, necessitating urgent evaluation and intervention to ensure the well-being of the fetus. Choices B, C, and D do not indicate immediate fetal distress requiring urgent intervention. Ruptured amniotic membrane, onset of uterine contractions, and leaking amniotic fluid are important assessments but do not present an immediate threat to the fetus's life like a severely low fetal heart rate.

Correct Answer: C

Rationale: Teratogens are environmental agents, such as drugs, chemicals, or infections, that can cause harm to a developing embryo or fetus. Mutations (Choice A) refer to changes in the DNA sequence and are not environmental agents. Autosomes (Choice B) are chromosomes that are not involved in determining an individual's sex and are not environmental agents that harm the embryo or fetus. Androgens (Choice D) are a group of hormones that are more related to male sexual development and function, not environmental agents that harm the embryo or fetus.

Correct Answer: C

Rationale: The nurse should recognize that dark stools are a common side effect in clients who are taking iron replacement therapy. Dark stools are a known, expected result of iron supplementation and are not indicative of a complication unless other symptoms of GI bleeding are present. A guaiac test would be necessary if there were concerns about gastrointestinal bleeding. Recognizing dark stools as a consequence of iron therapy is an essential nursing assessment skill and does not require immediate reporting. Checking the next stool to confirm the observation is unnecessary as the presence of dark stools in this context is already an expected outcome of iron supplementation.

Correct Answer: A

Rationale: Rico's symptoms align with Klinefelter syndrome, which is characterized by an extra X chromosome in males (XXY). Enlarged breasts (gynecomastia), mild mental retardation, learning difficulties, and reduced testosterone production are common features of Klinefelter syndrome. Choice B, Tay-Sachs disease, is a genetic disorder that affects the nervous system and is not associated with the symptoms described. Choice C, Turner syndrome, occurs in females with a missing or partially missing X chromosome and does not fit Rico's profile. Choice D, Down syndrome, is caused by an extra copy of chromosome 21 and typically does not present with the symptoms mentioned for Rico.