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. Which energy conversion occurs in a solar cell?

A. Electrical energy to light energy
B. Chemical energy to electrical energy
C. Solar energy to thermal energy
D. Solar energy to electrical energy

Correct answer: d

Rationale: Solar cells convert solar energy (sunlight) directly into electrical energy.

3. What is the main function of the epiglottis, a small flap of cartilage located above the larynx?

A. To warm and humidify inhaled air
B. To control the passage of food and air
C. To produce sound vibrations for speech
D. To sense the presence of foreign objects

Correct answer: B

Rationale: The correct answer is B: 'To control the passage of food and air.' The epiglottis is a crucial structure that prevents food and liquids from entering the airway during swallowing. It acts as a lid over the trachea, ensuring that food goes down the esophagus while air passes into the respiratory system. This function is essential for preventing choking and ensuring proper breathing. Options A, C, and D are incorrect as the epiglottis is not primarily responsible for warming and humidifying inhaled air, producing sound vibrations for speech, or sensing foreign objects.

4. The constituents of an atomic nucleus consist of:

A. Electrons and protons only
B. Protons and neutrons only
C. Electrons, protons, and neutrons
D. None of the above

Correct answer: B

Rationale: The correct answer is B: "Protons and neutrons only." This is because the atomic nucleus is composed of protons, which carry a positive charge, and neutrons, which are neutral. Electrons are found outside the nucleus in electron shells. Protons and neutrons are collectively known as nucleons and are responsible for the mass of the atom. Electrons are much lighter and are involved in chemical reactions and bonding. Therefore, the constituents of an atomic nucleus are specifically protons and neutrons, making option B the correct choice.

5. Which organ plays a significant role in immune cell production and maturation?

A. Liver
B. Kidneys
C. Bone marrow
D. Spleen

Correct answer: C

Rationale: The correct answer is C: Bone marrow. The bone marrow is the primary site for the production and maturation of immune cells, including white blood cells, which are crucial for the body's immune response. Stem cells in the bone marrow differentiate into various types of immune cells, such as T cells, B cells, and natural killer cells, which play essential roles in fighting infections and diseases. While the liver and kidneys have other important functions in the body, such as filtering toxins and metabolizing substances, they are not directly involved in immune cell production and maturation. The spleen acts as a reservoir for blood and is involved in filtering blood and storing red blood cells but is not the primary site for immune cell production.

6. Describe the concept of inertia in terms of Newton's first law.

A. Objects in motion tend to remain in motion unless acted upon by an external force
B. Objects at rest tend to remain at rest unless acted upon by an external force
C. An object's resistance to a change in its state of motion
D. The force required to lift an object

Correct answer: c

Rationale: Inertia refers to an object's tendency to maintain its current state of motion (either at rest or in motion) unless acted upon by an external force.