1. You design an experiment to test the effect of temperature on plant growth. Which variable should you keep constant?

A. The type of soil used.
B. The amount of sunlight the plants receive.
C. The amount of water given to the plants.
D. The temperature variations being tested.

Correct answer: A

Rationale: In this experiment, the variable being tested is the effect of temperature on plant growth. To ensure that any observed changes in plant growth are due to temperature variations and not other factors, it is important to keep other variables constant. The type of soil used can significantly impact plant growth, so it should be kept constant to isolate the effect of temperature. Keeping the amount of sunlight and water constant would also help ensure that any differences in plant growth are due to temperature variations.

2. Which of the following sentences uses the most formal language?

A. The movie was awesome!
B. The film did not meet my expectations.
C. I found the cinematic experience to be unsatisfactory.
D. The flick was pretty bad.

Correct answer: C

Rationale: The sentence uses more complex vocabulary ("cinematic experience") and avoids slang ("awesome," "flick").

3. 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.

4. Which type of glial cell provides structural support and insulation for neurons in the central nervous system?

A. Schwann cells
B. Astrocytes
C. Oligodendrocytes
D. Microglia

Correct answer: C

Rationale: The correct answer is C: Oligodendrocytes. Oligodendrocytes are a type of glial cell found in the central nervous system that provide structural support and insulation for neurons by forming myelin sheaths around axons. Schwann cells, on the other hand, are found in the peripheral nervous system. Astrocytes play a role in nutrient transfer and maintaining the blood-brain barrier. Microglia are responsible for immune defense and clearing debris in the CNS. Therefore, oligodendrocytes are specifically responsible for providing structural support and insulation for neurons in the central nervous system.

5. Nuclear forces are much stronger than electromagnetic forces at the nuclear level. What property best describes this characteristic?

A. Short-range interaction
B. Long-range interaction
C. Repulsive force
D. Dependent on charge only

Correct answer: A

Rationale: Nuclear forces operate within a very small range compared to electromagnetic forces, impacting only nucleons directly touching each other.

6. The primary function of the respiratory system is to:

A. Maintain body temperature
B. Deliver oxygen to the bloodstream and remove carbon dioxide
C. Produce antibodies for the immune system
D. Break down food molecules for energy

Correct answer: B

Rationale: The correct answer is B: 'Deliver oxygen to the bloodstream and remove carbon dioxide.' The primary function of the respiratory system is to facilitate gas exchange. When we breathe in, oxygen is inhaled and transported to the bloodstream, where it is delivered to cells for energy production. Simultaneously, carbon dioxide, a waste product of cellular metabolism, is removed from the bloodstream and exhaled. This process is vital for sustaining life and maintaining proper oxygen levels in the body. The respiratory system does not primarily regulate body temperature, produce antibodies, or break down food molecules for energy, making options A, C, and D incorrect.