1. Which of the following is NOT a risk factor for developing atherosclerosis?

A. High blood pressure
B. High levels of LDL cholesterol
C. Regular physical activity
D. Smoking

Correct answer: C

Rationale: Regular physical activity is NOT a risk factor for developing atherosclerosis. In fact, engaging in regular physical activity can help reduce the risk of developing atherosclerosis by improving cardiovascular health, lowering blood pressure, and reducing LDL cholesterol levels. High blood pressure, high levels of LDL cholesterol, and smoking are all known risk factors for atherosclerosis. High blood pressure can damage blood vessels, making them more susceptible to plaque buildup. High levels of LDL cholesterol can lead to the accumulation of plaque in the arteries, narrowing the passageways and increasing the risk of atherosclerosis. Smoking is harmful to blood vessels, promoting inflammation and the formation of plaque. Therefore, regular physical activity is actually a protective factor against atherosclerosis rather than a risk factor.

2. A person throws a ball horizontally. What force changes the direction of the ball's motion?

A. The force of throwing
B. Gravitational force
C. Air resistance
D. Normal force from the ground

Correct answer: B

Rationale: When a person throws a ball horizontally, the initial force that propels the ball forward is the force of throwing (A). However, the force that changes the direction of the ball's motion is the gravitational force (B), which acts vertically downward and causes the ball to follow a curved path. Air resistance (C) and normal force from the ground (D) do not directly change the direction of the ball's motion in this scenario.

3. Identify the adjective in the following sentence: The colorful sunset painted the sky with vibrant hues.

A. sunset
B. with
C. colorful
D. painted

Correct answer: C

Rationale: Adjectives modify nouns and pronouns. The adjective "colorful" describes the noun "sunset".

4. What is the role of RNA interference in silencing genes?

A. Increases protein production
B. Promotes gene mutation
C. Inhibits the expression of specific genes
D. Repairs damaged DNA

Correct answer: C

Rationale: Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, "Inhibits the expression of specific genes," is the correct role of RNA interference in silencing genes.

5. Which of the following is an example of a nonpolar solvent?

A. Water
B. Ethanol
C. Acetone
D. Hydrochloric acid

Correct answer: B

Rationale: Rationale: - Water (option A) is a polar solvent due to its uneven distribution of charge, with the oxygen atom being partially negative and the hydrogen atoms being partially positive. - Ethanol (option B) is a nonpolar solvent because it has a symmetrical molecular structure that does not result in significant charge separation. - Acetone (option C) is a polar solvent as it contains a carbonyl group that results in a partial negative charge on the oxygen atom. - Hydrochloric acid (option D) is a polar solvent due to the presence of the highly electronegative chlorine atom, which results in a partial negative charge.

6. Centrioles are structures involved in cell division. What is their specific role?

A. Forming the nuclear envelope
B. Replicating DNA
C. Organizing microtubules during cell division
D. Protein synthesis

Correct answer: C

Rationale: Centrioles are cylindrical structures found in animal cells that play a crucial role in organizing microtubules during cell division. They form the spindle fibers that help separate chromosomes during mitosis and meiosis. This organization is essential for the proper alignment and separation of chromosomes, ensuring accurate distribution of genetic material to daughter cells. Centrioles do not participate in forming the nuclear envelope, replicating DNA, or protein synthesis. Therefore, the correct answer is C, as centrioles are primarily involved in microtubule organization to facilitate cell division.