1. Scientific findings are constantly evolving. This emphasizes the importance of:

A. Unquestioning belief in established theories and models.
B. Dogmatically adhering to the opinions of prominent scientists.
C. Maintaining an open mind and willingness to consider new evidence.
D. Prioritizing quick and decisive answers over careful evaluation.

Correct answer: C

Rationale: Science is a dynamic process built on continual questioning and refining of understanding. Openness to new evidence and revision of existing theories is crucial for scientific progress.

2. Vaccines work by stimulating the immune system to develop:

A. A physical barrier against pathogens
B. An inflammatory response
C. Immunological memory to a specific pathogen
D. Phagocytes to engulf pathogens

Correct answer: C

Rationale: The correct answer is C: 'Immunological memory to a specific pathogen.' Vaccines work by introducing a harmless form of a pathogen or a piece of it to stimulate the immune system. This exposure triggers the production of antibodies and memory cells specific to that pathogen. These memory cells 'remember' the pathogen, allowing the immune system to respond more effectively and rapidly if exposed to the actual pathogen in the future. Options A, B, and D are incorrect because vaccines do not create a physical barrier, induce a general inflammatory response, or directly cause phagocytes to engulf pathogens; instead, vaccines enhance the immune system's ability to recognize and combat specific pathogens.

3. What is the term for the process of exchanging gases (oxygen and carbon dioxide) between the blood and the tissues?

A. Inhalation
B. Exhalation
C. External respiration
D. Internal respiration

Correct answer: D

Rationale: The correct answer is D: 'Internal respiration.' Internal respiration refers to the process where oxygen is exchanged for carbon dioxide between the blood and the body tissues at the cellular level. Inhalation (A) and exhalation (B) pertain to the movement of air into and out of the lungs. External respiration (C) involves the exchange of gases between the lungs and the bloodstream. Understanding internal respiration is crucial as it directly impacts the body's ability to supply oxygen to tissues and remove carbon dioxide, which is essential for cellular function and overall health.

4. A salt solution that conducts electricity well is most likely

A. A saturated solution
B. A concentrated solution of a strong electrolyte
C. A dilute solution of a weak acid
D. A mixture of a neutral compound and water

Correct answer: B

Rationale: The correct answer is B: "A concentrated solution of a strong electrolyte." Strong electrolytes completely dissociate into ions in solution, thereby increasing the conductivity of the solution. Concentrated solutions have a higher amount of dissolved solute particles, which leads to more ions available for conducting electricity. In contrast, saturated solutions may contain undissolved solute, limiting the number of ions in solution. Dilute solutions have fewer ions and weak acids only partially dissociate, reducing conductivity. A neutral compound and water do not provide ions for conducting electricity. Therefore, a concentrated solution of a strong electrolyte is most likely to conduct electricity well due to the high concentration of ions present.

5. Which of the following is NOT a function of the integumentary system?

A. Regulation of body temperature
B. Protection from pathogens
C. Synthesis of vitamin D
D. Production of digestive enzymes

Correct answer: D

Rationale: The correct answer is D: "Production of digestive enzymes." The integumentary system primarily consists of the skin, hair, nails, and glands. Its main functions include regulating body temperature through processes like sweating and shivering, protecting the body from pathogens and external threats, and synthesizing vitamin D when exposed to sunlight. However, the production of digestive enzymes is not a function of the integumentary system. Digestive enzymes are primarily produced by organs such as the pancreas and salivary glands to aid in the breakdown of food in the digestive system, which is separate from the functions of the integumentary system.