In a randomized controlled trial (RCT), participants are randomly assigned to either the experimental or the control group to:

Correct Answer: B

Rationale: The correct answer is B: Minimize selection bias. Random assignment in an RCT helps ensure that participants in the experimental and control groups are similar at baseline. This minimizes the risk of selection bias, where certain characteristics of participants influence study outcomes. Choice A is incorrect because the purpose of random assignment is not specifically to test treatment effectiveness but to minimize bias. Choice C is incorrect because random assignment does not directly increase sample size. Choice D is incorrect because providing a baseline measurement is not the primary purpose of random assignment in an RCT.

Correct Answer: B

Rationale: The correct answer is B: Leave the pimple. Pinching a pimple can lead to inflammation, scarring, and further spread of bacteria. Leaving the pimple allows it to heal naturally, reducing the risk of complications. It is important to practice gentle skincare to promote healthy skin and avoid causing damage or irritation. Other choices are incorrect as they involve actions that can harm the skin and worsen the condition.

Correct Answer: B

Rationale: The correct answer is B: Hypothermia. Subnormal core body temperature indicates the body temperature is below normal range, which is characteristic of hypothermia. Hyperthermia refers to elevated body temperature, making choice A incorrect. Choices C and D are likely not provided as they do not directly relate to the concept of body temperature.

Correct Answer: B

Rationale: The correct answer is B: Clear and light sample. This is because sputum should ideally be clear and light in color, indicating a lower presence of mucus and other contaminants. A cloudy, thick sample (choice A) may indicate an infection or presence of pus. Choices C and D are likely left blank as they are irrelevant or incorrect responses. In summary, a clear and light sputum sample is preferred for accurate testing and diagnosis.

Correct Answer: B

Rationale: The correct answer is B: Intact skin. Intact skin acts as the first defense against infection by forming a physical barrier that prevents pathogens from entering the body. It is composed of multiple layers, including the epidermis and dermis, which provide protection against microbes. Skin also produces antimicrobial substances and has immune cells that can defend against pathogens. A: Skin is not specific enough, as damaged skin may not provide effective protection. C and D are incomplete answers and do not accurately describe the primary role of intact skin in defending against infections.