1. The innate immune system provides:

A. Nonspecific, immediate defense against pathogens
B. Specific, long-term immune response through memory cells
C. Both (a) and (b)
D. Neither (a) nor (b)

Correct answer: A

Rationale: The correct answer is A: 'Nonspecific, immediate defense against pathogens.' The innate immune system is the body's first line of defense against pathogens and provides a rapid, nonspecific response. It includes physical barriers like the skin, chemical barriers like stomach acid, and cellular responses like inflammation. This system does not involve memory cells or provide long-term immunity, which are characteristics of the adaptive immune system. Therefore, option A accurately describes the function of the innate immune system as a quick and nonspecific defense mechanism.

2. In the reaction 2Na + 2H2O Ã¢â€ â€™ 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

A. Na
B. H2O
C. NaOH
D. H2

Correct answer: a

Rationale: Sodium is the limiting reactant because it runs out first in a 1:1 ratio with water.

3. Which sentence uses the semicolon correctly?

A. The play was long; however, it was very entertaining.
B. The guests arrived; Sarah greeted them at the door.
C. John likes apples; Mary prefers oranges.
D. He was tired; he went to bed early.

Correct answer: B

Rationale: Option B joins two independent clauses related to the same event.

4. A study finds a specific gene linked to increased risk of heart disease. Does this mean everyone with that gene will develop heart disease?

A. Yes, the gene deterministically causes heart disease.
B. No, other factors also influence heart disease risk.
C. We need more research to clarify the gene's exact role.
D. Only people with a family history of heart disease need to worry.

Correct answer: B

Rationale: The presence of a specific gene linked to an increased risk of heart disease does not guarantee that everyone with that gene will develop the condition. Other factors such as lifestyle, environment, and overall health also play a significant role in determining an individual's risk of heart disease. Therefore, it is essential to consider these additional factors rather than solely attributing the risk to the gene itself.

5. What is the structure that attaches to each chromosome during mitosis?

A. Centromere
B. Telomere
C. Spindle apparatus
D. Nucleolus

Correct answer: A

Rationale: Rationale: The centromere is the structure that attaches to each chromosome during mitosis. It is a region of the chromosome where the two sister chromatids are held together and where the spindle fibers attach during cell division. The centromere plays a crucial role in ensuring that each daughter cell receives the correct number of chromosomes during cell division. Telomeres are structures found at the ends of chromosomes that protect them from deterioration and fusion with neighboring chromosomes. The spindle apparatus is a structure made of microtubules that helps separate chromosomes during cell division. The nucleolus is a region within the nucleus where ribosomal RNA synthesis occurs and is not directly involved in chromosome attachment during mitosis.

6. Which hormone, produced by the adrenal glands, is essential for the regulation of electrolyte balance, particularly sodium and potassium, in the body?

A. Aldosterone
B. Epinephrine
C. Cortisol
D. Insulin

Correct answer: A

Rationale: The correct answer is A: Aldosterone. Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in regulating electrolyte balance, especially sodium and potassium levels in the body. It acts on the kidneys to increase the reabsorption of sodium and excretion of potassium, which helps to maintain proper fluid balance and blood pressure. Epinephrine (B) is involved in the 'fight or flight' response, cortisol (C) is a stress hormone, and insulin (D) regulates blood sugar levels, but neither of these hormones primarily regulates electrolyte balance like aldosterone does.