monozygotic mz twins share percent of their genes
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1. Monozygotic (MZ) twins share _________ percent of their genes.

Correct answer: A

Rationale: Monozygotic (MZ) twins share 100% of their genes because they originate from the same fertilized egg that splits into two, resulting in identical genetic material for both twins. Choice B (75%) is incorrect as it implies a partial genetic similarity, which is not the case for MZ twins. Choice C (50%) is incorrect as it suggests half of the genes are shared, which is applicable to dizygotic (DZ) twins, not MZ. Choice D (25%) is incorrect as it indicates minimal genetic sharing, which is not true for MZ twins.

2. When assessing a woman in the first stage of labor, which clinical finding will alert the nurse that uterine contractions are effective?

Correct answer: A

Rationale: During the first stage of labor, effective uterine contractions lead to cervical dilation. Dilation of the cervix is a key indicator that uterine contractions are progressing labor. Descent of the fetus to -2 station (Choice B) is related to the fetal position in the pelvis and not a direct indicator of uterine contraction effectiveness. Rupture of the amniotic membranes (Choice C) signifies the rupture of the fluid-filled sac surrounding the fetus and does not directly reflect uterine contraction effectiveness. An increase in bloody show (Choice D) can be a sign of impending labor, but it is not a direct indicator of uterine contraction effectiveness.

3. Once the testes have developed in the embryo, they begin to produce male sex hormones, or _____.

Correct answer: A

Rationale: Androgens are male sex hormones, such as testosterone, produced by the testes after they have developed in the embryo. Androgens are responsible for the development of male secondary sexual characteristics. Genotypes refer to an individual's genetic makeup, not hormones. Blastocysts are early stage embryos, not male sex hormones. Teratogens are substances that can interfere with fetal development, not male sex hormones produced by the testes.

4. Which of the following pairs share 100% of their genes?

Correct answer: D

Rationale: The correct answer is Monozygotic (MZ) twins. Monozygotic twins, also known as identical twins, share 100% of their genes because they originate from the same fertilized egg that splits into two. Fraternal twins (choice B), also known as dizygotic (DZ) twins (choice C), result from two separate fertilized eggs and share approximately 50% of their genes. Biovular twins (choice A) is not a term used in genetics and does not describe a type of twinning.

5. According to a survey by Adhikari and Liu in the year 2013, at birth, women have:

Correct answer: B

Rationale: Women are born with approximately 300,000 to 400,000 ova, which gradually decrease in number as they age. Choice A ('close to 100,000 ova.') is incorrect as the actual number is much higher. Choice C ('around 100 to 200 ova.') is incorrect as it underestimates the quantity significantly. Choice D ('only 500 ova.') is incorrect as it greatly underestimates the number of ova present at birth.

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