Nursing Elites

1. Do dizygotic (DZ) twins run in families?

• A. Yes
• B. No
• C. Rarely
• D. Never

Correct answer: A

Rationale: Yes, dizygotic (DZ) twins can run in families. This is due to genetic factors that influence hyperovulation, where a woman releases multiple eggs during her menstrual cycle. This genetic predisposition can be passed down through generations, increasing the likelihood of having dizygotic twins. Choices B, C, and D are incorrect because the statement that dizygotic twins run in families is true, as supported by scientific evidence. It is important to note that while the genetic predisposition for dizygotic twins can run in families, it does not guarantee that every generation will have twins, as other factors also play a role in twin pregnancies.

2. _____ are environmental agents that can harm the embryo or fetus.

• A. Mutations
• B. Autosomes
• C. Teratogens
• D. Androgens

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.

3. Is color blindness a sex-linked abnormality?

• A. TRUE
• B. FALSE
• C. Sometimes
• D. Always

Correct answer: A

Rationale: The correct answer is A: TRUE. Color blindness is indeed a sex-linked abnormality as it is often associated with genes on the X chromosome. Since males have only one X chromosome, they are more likely to inherit color blindness if the gene is present. This makes color blindness more common in males. Choice B (FALSE) is incorrect because color blindness is linked to the X chromosome. Choices C (Sometimes) and D (Always) are incorrect as color blindness is consistently tied to the X chromosome.

4. What is the central layer of the embryo from which the bones and muscles develop?

• A. neural tube
• B. mesoderm
• C. ectoderm
• D. umbilical cord

Correct answer: B

Rationale: The correct answer is mesoderm. The mesoderm is the middle layer of the embryo that gives rise to the bones, muscles, and other connective tissues. The neural tube (choice A) develops into the nervous system, not bones and muscles. The ectoderm (choice C) forms the skin and nervous system, not bones and muscles. The umbilical cord (choice D) is a structure that connects the developing fetus to the placenta; it is not a layer of the embryo that gives rise to bones and muscles.

5. Which of the following statements is true of a sperm cell?

• A. A sperm cell is significantly larger than an egg cell.
• B. A sperm cell contains two Y chromosomes.
• C. A sperm cell travels randomly inside a woman’s reproductive tract.
• D. A sperm cell is one of the smallest types of cells in the body.

Correct answer: D

Rationale: The correct answer is D. A sperm cell is indeed one of the smallest cells in the human body, much smaller than an egg cell. Choice A is incorrect as sperm cells are much smaller than egg cells. Choice B is incorrect because a sperm cell carries either an X or a Y chromosome, not two Y chromosomes. Choice C is incorrect since sperm cells move in a purposeful manner guided by various factors within a woman's reproductive tract, not randomly.

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