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 sentence uses the present perfect continuous tense correctly?

A. I have been working on this project since morning.
B. She has finished the book already.
C. They will be leaving for vacation tomorrow.
D. He had been living in the city for ten years.

Correct answer: A

Rationale: Option A emphasizes the ongoing action (working) that started in the past and continues to the present.

3. What happens to the potential energy of an object when it is lifted higher above the ground?

A. Potential energy decreases
B. Potential energy remains the same
C. Potential energy increases
D. Potential energy becomes zero

Correct answer: C

Rationale: When an object is lifted higher above the ground, its potential energy increases because the higher the object is lifted, the greater its potential energy due to the increased distance from the ground. This is in accordance with the formula for gravitational potential energy, which is PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height above the reference point.

4. Lysosomes are known as "suicide bags" of the cell. What enzymes do they contain?

A. Hydrolytic enzymes
B. Ligases (bonding enzymes)
C. Transferases (molecule transfer)
D. Oxidoreductases (redox reactions)

Correct answer: A

Rationale: Lysosomes are membrane-bound organelles containing hydrolytic enzymes responsible for breaking down various macromolecules, cellular waste, and foreign substances. These enzymes perform hydrolysis, a process where water molecules are used to break down larger molecules into smaller components. This function earned lysosomes the nickname 'suicide bags' as they can initiate cell death (apoptosis) by releasing their enzymes when needed. Ligases, transferases, and oxidoreductases are enzymes with different functions such as forming bonds, transferring molecules, and catalyzing redox reactions, respectively, which are not typically found in lysosomes. Therefore, the correct answer is A: 'Hydrolytic enzymes.'

5. A hypothesis should be:

A. A definitive statement of fact based on existing knowledge.
B. A testable prediction based on observations and reasoning.
C. A broad question without any specific direction or focus.
D. A personal belief or opinion not requiring further investigation.

Correct answer: B

Rationale: Hypotheses guide scientific exploration by providing a framework for testing potential explanations.

6. Which respiratory structure is responsible for the production of mucus to trap particles and for the movement of cilia to sweep mucus and trapped particles out of the respiratory tract?

A. Trachea
B. Larynx
C. Bronchi
D. Respiratory epithelium

Correct answer: D

Rationale: The correct answer is D: Respiratory epithelium. The respiratory epithelium is a specialized tissue lining the respiratory tract that produces mucus to trap particles and contains cilia that beat in a coordinated manner to move the mucus and trapped particles out of the respiratory tract. The trachea, larynx, and bronchi are all structures within the respiratory system, but they do not directly produce mucus or have cilia for sweeping particles. Therefore, the respiratory epithelium is the specific structure responsible for these functions.