According to a study in 2013 by van Gameren-Oosterom, individuals with Down syndrome:

Correct Answer: C

Rationale: The correct answer is C. According to a study in 2013 by van Gameren-Oosterom, individuals with Down syndrome often exhibit deficits in cognitive development. This is a common characteristic of Down syndrome, along with other health challenges. Choice A is incorrect because individuals with Down syndrome are at a higher risk of cardiovascular problems, contrary to being unlikely to die from them. Choice B is incorrect as Down syndrome is associated with specific characteristic features such as distinctive facial characteristics, making the statement that they have no specific features incorrect. Choice D is incorrect as individuals with Down syndrome have an extra copy of chromosome 21, resulting in a total of 47 chromosomes, not 46.

Correct Answer: C

Rationale: Cystic fibrosis is a genetic disorder caused by inheriting two copies of a recessive gene, one from each parent. This means that both parents must carry at least one copy of the faulty gene for a child to inherit the condition. Choice A is incorrect because cystic fibrosis is not linked to the sex chromosomes. Choice B is incorrect as cystic fibrosis is not caused by an abnormality in the 21st pair of chromosomes but by a specific gene mutation. Choice D is also incorrect as cystic fibrosis is not related to the Y chromosome, which is specific to males.

Correct Answer: D

Rationale: The correct answer is the Alpha-fetoprotein (AFP) assay. This blood test measures the level of AFP in a pregnant woman's blood, aiding in the detection of neural tube defects and certain chromosomal abnormalities in the fetus. Choice A, artificial insemination, is a method used to facilitate fertilization and is not related to detecting fetal abnormalities. Choice B, amniocentesis, involves collecting amniotic fluid for genetic testing, not directly measuring AFP levels. Choice C, endometriosis, is a medical condition involving abnormal tissue growth and is not a procedure for detecting fetal abnormalities. Therefore, the Alpha-fetoprotein (AFP) assay is the most appropriate option for detecting neural tube defects such as spina bifida and certain chromosomal abnormalities.

Correct Answer: C

Rationale: The correct answer is C: uterus. The uterus is the organ where the embryo implants and the fetus develops during pregnancy. The placenta (choice A) is an organ that develops during pregnancy and provides nutrients and oxygen to the fetus, but it is not the organ where the embryo and fetus physically develop. The ovum (choice B) is the female reproductive cell or egg that is fertilized by the sperm to form an embryo, but it is not the organ where the embryo and fetus develop. The amniotic sac (choice D) is a membrane filled with amniotic fluid that surrounds and protects the fetus, but it is not the organ where the embryo and fetus physically develop.

Correct Answer: D

Rationale: The correct answer is 'Positive fetal hemoglobin testing' (D). Positive fetal hemoglobin testing (Kleihauer-Betke test) indicates fetal-maternal hemorrhage, which is critical in an RH-negative mother due to the risk of isoimmunization. This condition can lead to sensitization of the mother's immune system against fetal blood cells, potentially causing hemolytic disease of the newborn in subsequent pregnancies. Reporting this finding promptly is crucial for appropriate management and interventions. Choices A, B, and C are not as critical in this scenario. While monitoring fetal heart rate and contractions is important, the detection of fetal-maternal hemorrhage takes precedence due to the serious implications it poses for the current and future pregnancies of an RH-negative mother.

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: D

Rationale: According to the study, the chances of a woman bearing twins increase if she is a twin herself, if her mother was a twin, or if she has previously borne twins. Therefore, the correct answer is D. Choice A is incorrect because the study does not specify that she will bear only monozygotic twins. Choice B is incorrect as the study does not mention any decrease in the chances of becoming pregnant. Choice C is incorrect because the study does not provide information about the woman's health status, focusing instead on the likelihood of bearing twins.

Correct Answer: A

Rationale: A contraction duration of 100 seconds is too long and can indicate uterine hyperstimulation, which can lead to fetal distress and other complications. This prolonged contraction duration suggests that the uterus is not relaxing adequately between contractions, potentially compromising fetal oxygenation. Choice B, 'Four contractions in 10 minutes,' is a sign of tachysystole, which is concerning but not as immediately critical as the prolonged contraction duration. Choice C, 'Uterus is soft,' is not a reason to discontinue oxytocin; in fact, it is a normal finding. Choice D, 'Early deceleration of fetal heart rate,' while indicating fetal distress, is not a direct result of the oxytocin and may require intervention but not immediate discontinuation of the medication.

Correct Answer: B

Rationale: The correct answer is B: 'FALSE.' Monozygotic (MZ) twins are identical twins, not fraternal. Fraternal twins are dizygotic (DZ). The statement in the question is incorrect as MZ twins are genetically identical, while fraternal twins actually refer to dizygotic twins who develop from two separate fertilized eggs. Therefore, monozygotic twins are not known as fraternal twins, making option B the correct choice. Options A, C, and D are incorrect as they do not accurately describe the relationship between monozygotic and fraternal twins.