1. Which structure contains the genetic material (DNA) of the cell?

A. Cytoplasm
B. Nucleus
C. Cell wall (only present in plant cells)
D. Golgi apparatus

Correct answer: B

Rationale: The correct answer is B: Nucleus. The nucleus is the organelle that contains the genetic material (DNA) of the cell. It acts as the control center of the cell, regulating gene expression and coordinating cellular activities. The cytoplasm, option A, is the jelly-like substance that fills the cell and surrounds the organelles, but it does not contain the genetic material. The cell wall, option C, is a rigid structure found in plant cells that provides support and protection, but it does not house the DNA. The Golgi apparatus, option D, is responsible for modifying, sorting, and packaging proteins for secretion, but it does not store the genetic material of the cell. Therefore, the nucleus is the structure that contains the genetic material in a cell.

2. The process of a liquid changing into a gas is called:

A. Evaporation
B. Boiling
C. Condensation
D. Sublimation

Correct answer: A

Rationale: Evaporation occurs at any temperature, while boiling only occurs at the boiling point of the liquid.

3. 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.

4. What happens to the kinetic energy of an object when its mass is doubled?

A. Kinetic energy remains the same
B. Kinetic energy halves
C. Kinetic energy doubles
D. Kinetic energy quadruples

Correct answer: c

Rationale: Kinetic energy is directly proportional to the square of an object's mass when its velocity remains constant.

5. What is the term for the first exposure to a specific pathogen, leading to the development of an initial immune response?

A. Primary immune response
B. Secondary immune response
C. Hypersensitivity reaction
D. Immunological tolerance

Correct answer: A

Rationale: The correct answer is A: 'Primary immune response.' The primary immune response refers to the initial encounter with a specific pathogen, which triggers the immune system to respond by producing antibodies and memory cells. This process lays the foundation for the secondary immune response, which occurs upon subsequent exposure to the same pathogen. The primary immune response is characterized by the lag time in antibody production as the immune system is mobilized to combat the new threat. In contrast, the secondary immune response is faster and more robust due to the presence of memory cells from the primary response. Hypersensitivity reactions involve an exaggerated immune response to an antigen, while immunological tolerance refers to the immune system's ability to recognize self from non-self to prevent autoimmunity.