1. The bones of the skull are classified as what type of bone?

A. Long bone
B. Short bone
C. Flat bone
D. Irregular bone

Correct answer: C

Rationale: The correct answer is C: Flat bone. The bones of the skull are classified as flat bones due to their thin, flattened shape. Flat bones provide protection to vital organs and have a broad surface for muscle attachment. Long bones, like the femur, are characterized by their elongated shape, while short bones, such as those in the wrist and ankle, are cube-shaped. Irregular bones have complex shapes and do not fit into the other bone categories. In this case, the flat bones of the skull best fit the classification.

2. The van't Hoff factor (i) accounts for the number of particles a solute dissociates into in solution. For a compound that dissociates completely in water, i would be...

A. 0
B. Less than 1
C. 1
D. More than 1

Correct answer: C

Rationale: The van't Hoff factor (i) is used to account for the number of particles a solute dissociates into in solution. For a compound that dissociates completely in water, such as a strong electrolyte, i would be equal to the total number of ions produced by the dissociation. Since the compound dissociates completely, it forms an equal number of ions, resulting in an i value of 1. Therefore, the correct answer is C: 1.

3. 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.

4. Sunscreen protects the skin from harmful ultraviolet (UV) rays by

A. Reflecting UV rays away from the skin
B. Absorbing UV rays and converting them to heat
C. Blocking UV rays completely
D. Stimulating melanin production

Correct answer: B

Rationale: The correct answer is B: Absorbing UV rays and converting them to heat. Sunscreen contains ingredients that act as filters to absorb UV radiation before it reaches the skin. These filters then convert the UV rays into a less harmful form of energy, usually heat, which is then released from the body. This process helps prevent UV radiation from damaging the skin cells and causing sunburn or long-term skin damage. Reflecting UV rays away from the skin (A) and blocking UV rays completely (C) are not accurate functions of sunscreen. Additionally, stimulating melanin production (D) is not a direct way in which sunscreen protects the skin from UV rays.

5. Which of the following is NOT a typical component of healthy semen?

A. Sperm
B. Fructose (sugar)
C. Prostaglandins
D. Urine

Correct answer: D

Rationale: The correct answer is D: Urine. Semen is a mixture of fluids from various glands in the male reproductive system. It typically contains sperm, fructose (sugar) to provide energy for the sperm, and prostaglandins to aid in sperm motility. Urine is not a normal component of healthy semen. It is important to note that urine and semen travel through different pathways in the male body, and they should not mix. Therefore, the presence of urine in semen would indicate a potential issue or infection in the urinary system. Understanding the components of healthy semen is crucial for assessing male reproductive health and fertility.

6. A baseball is thrown into the air. At the peak of its trajectory, which of the following forces is acting on the ball?

A. Only gravitational force
B. Only the force of air resistance
C. Both gravitational force and the force of air resistance
D. Neither gravitational force nor the force of air resistance

Correct answer: A

Rationale: At the peak, the ball momentarily stops moving upwards. Its inertia keeps it moving horizontally, but there is no force propelling it upwards except for gravity pulling it down.