Biology HESI A2 Practice Exam

Correct Answer: C

Rationale: The correct answer is C: One daughter may have the disease. This is because Duchenne muscular dystrophy is a recessive sex-linked trait carried on the X chromosome. In this scenario, the unaffected father will pass his Y chromosome to his sons, making them unaffected carriers. The mother, being a carrier, has a 50% chance of passing the affected X chromosome to each daughter, resulting in a 50% chance that one daughter may have the disease. The other choices are incorrect because both sons cannot inherit the disease from the mother, and both daughters cannot carry the disease as they would either be unaffected carriers or affected themselves.

Correct Answer: D

Rationale: The correct answer is D because salt is corrosive and breaks down the slug's cell walls, leading to dehydration and ultimately killing the slug. When salt comes into contact with the slug's moist body, it absorbs water from the slug's cells, causing damage and dehydration. Choices A, B, and C are incorrect as they do not accurately explain the mechanism of how salt affects slugs. Salt does not move into the slug's body, cause water to move outward, or merge with slug slime to form a new compound.

Correct Answer: A

Rationale: The correct answer is A: Anther. The anther is the part of the plant responsible for producing pollen. It is located at the top of the stamen, one of the male reproductive parts of a flower. Pollen contains the male gametes necessary for fertilization. The other choices, B: Style, C: Stigma, and D: Pistil, are all parts of the female reproductive system of a flower. The style is the tube connecting the stigma to the ovary, the stigma is the sticky part that receives pollen, and the pistil is the entire female reproductive structure. Therefore, they are not involved in the production of pollen.

Correct Answer: A

Rationale: The correct answer is A: Sucrose. Sucrose is a disaccharide composed of one molecule of glucose and one molecule of fructose. It is formed by a condensation reaction between these two monosaccharides. Fructose (choice B), glucose (choice C), and galactose (choice D) are all monosaccharides, not disaccharides. Therefore, they are incorrect choices for this question.

Correct Answer: A

Rationale: The correct answer is A: Shelf fungus. Shelf fungi reproduce via spore formation, a process where specialized reproductive cells are released into the environment to germinate and grow into new individuals. This method is characteristic of fungi and some plants. The other choices, B: Lemon tree, C: Smallmouth bass, and D: Staphylococcus, reproduce through different mechanisms such as seeds, spawning, and binary fission, respectively. Spore formation is unique to certain organisms like fungi, making option A the correct answer.