1. 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.

2. The adaptive immune system has two main branches: humoral and cell-mediated immunity. Which type of immune cell is primarily responsible for antibody production?

A. Helper T cells
B. Cytotoxic T cells
C. B cells
D. Natural killer cells

Correct answer: C

Rationale: The correct answer is C: B cells. B cells are a type of lymphocyte that plays a central role in humoral immunity by producing antibodies. When activated by antigens, B cells differentiate into plasma cells, which are responsible for producing and secreting antibodies. Helper T cells (option A) primarily assist in activating B cells and other immune cells. Cytotoxic T cells (option B) are involved in cell-mediated immunity, where they directly kill infected cells. Natural killer cells (option D) are part of the innate immune system and target virus-infected and cancerous cells. Therefore, B cells are the immune cells primarily responsible for antibody production in the adaptive immune system.

3. Which of the following joints allows for side-to-side bending movements?

A. Hinge joint
B. Ball-and-socket joint
C. Gliding joint
D. Saddle joint

Correct answer: C

Rationale: The correct answer is C: Gliding joint. Gliding joints are found where the bones meet and allow for limited side-to-side and back-and-forth movements. These joints have flat or slightly curved surfaces that glide against each other, enabling smooth motion in multiple directions. Hinge joints (A) allow for movement in one plane like a door hinge, ball-and-socket joints (B) allow for a wide range of motion in multiple directions, and saddle joints (D) allow for back-and-forth and side-to-side movements but are primarily designed for flexion and extension like the joint at the base of the thumb.

4. What is the function of the cell membrane?

A. To protect the cell and control what enters and exits
B. To store energy
C. To produce proteins
D. To synthesize lipids

Correct answer: A

Rationale: Rationale: The cell membrane, also known as the plasma membrane, serves as a protective barrier for the cell, separating the internal environment of the cell from the external environment. It is selectively permeable, meaning it controls the passage of substances in and out of the cell. This regulation of what enters and exits the cell is crucial for maintaining the cell's internal environment and ensuring proper functioning. Options B, C, and D are incorrect because storing energy, producing proteins, and synthesizing lipids are functions carried out by other cellular structures such as mitochondria, ribosomes, and endoplasmic reticulum, respectively, not the cell membrane.

5. 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").

6. Which vitamin is essential for proper absorption of calcium and plays a role in lung function?

A. Vitamin A
B. Vitamin B12
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: The correct answer is C, Vitamin D. Vitamin D is essential for the proper absorption of calcium in the intestines, which is crucial for maintaining strong bones and teeth. Additionally, Vitamin D plays a role in lung function by supporting respiratory health and reducing inflammation in the lungs. Vitamin A is important for vision and immune function, Vitamin B12 is necessary for red blood cell formation and neurological function, and Vitamin E is an antioxidant that helps protect cells from damage.