what is the main purpose of recommended dietary allowances rdas

HESI LPN

LPN Nutrition Practice Test

1. What is the main purpose of Recommended Dietary Allowances (RDAs)?

A. To provide guidelines for nutrient intakes that meet the needs of most healthy people.
B. To specify the minimum amount of nutrients required for survival.
C. To establish maximum safe levels of nutrient intakes.
D. To recommend specific nutrient intake levels to prevent chronic diseases.

Correct answer: A

Rationale: The main purpose of Recommended Dietary Allowances (RDAs) is to provide guidelines for nutrient intakes that meet the needs of most healthy people. Choice B is incorrect because RDAs aim beyond just survival requirements. Choice C is incorrect because establishing maximum safe levels is the role of Tolerable Upper Intake Levels (ULs). Choice D is incorrect because preventing chronic diseases is more associated with Dietary Reference Intakes (DRIs) like Adequate Intakes (AIs) and Tolerable Upper Intake Levels (ULs). Therefore, the correct answer is A.

2. How much energy is required to raise the temperature of one kilogram of water by 1°C?

A. 10 calories
B. 100 calories
C. 1 kilocalorie
D. 10 kilocalories

Correct answer: C

Rationale: The correct answer is 1 kilocalorie. This is the amount of energy required to raise the temperature of 1 kilogram of water by 1°C. Choice A (10 calories) and Choice D (10 kilocalories) are incorrect as they do not represent the correct unit of measurement for this specific scenario. Choice B (100 calories) is also incorrect as it overestimates the amount of energy required. The specific heat capacity of water is approximately 1 calorie/gram °C, which means that 1 kilogram (1000 grams) of water requires 1 kilocalorie (1000 calories) to raise its temperature by 1°C.

3. What is one major weakness of a laboratory-based study?

A. The costs are typically prohibitive.
B. Findings are difficult to replicate.
C. Results from animal testing cannot be applied to human beings.
D. Experimental variables cannot be easily controlled.

Correct answer: C

Rationale: One major weakness of laboratory-based studies is that results from animal testing cannot always be applied to human beings. This limitation arises due to the inherent biological differences between animals and humans, making the generalization of findings challenging. While costs may be a concern in some cases, they do not represent a universal weakness of laboratory-based studies. Findings in such studies can be replicated to ensure validity, and experimental variables can be effectively controlled in a laboratory setting. Choice C is the correct answer because the translatability of results from animal studies to humans is a significant challenge in laboratory-based research, impacting the direct application of findings to human health and well-being.

4. Why is peer review important in scientific research?

A. To expedite publication of results.
B. To facilitate the replication of studies.
C. To verify the accuracy and validity of research findings.
D. To enhance the credibility of the research.

Correct answer: C

Rationale: Peer review is crucial in scientific research to verify the accuracy and validity of research findings. By subjecting research papers to evaluation by experts in the field, peer review ensures that the study's methods, results, and conclusions are robust and reliable. This process helps to maintain high standards of quality in scientific publications, providing credibility to the research. Choices A and D are incorrect because the primary purpose of peer review is not to expedite publication or solely enhance credibility; its core function is to validate the research's accuracy and validity. Choice B, while beneficial, is not the primary reason for peer review; replication is a byproduct of the rigorous evaluation of research methods and findings.

5. In the scientific method, a tentative solution to a problem is called a what?

A. theory
B. prediction
C. hypothesis
D. correlation

Correct answer: C

Rationale: In the scientific method, a hypothesis is a tentative solution or educated guess that is tested through research. A theory (choice A) is a well-substantiated explanation based on evidence and extensive testing. A prediction (choice B) is a statement about what will happen in the future based on existing knowledge. Correlation (choice D) refers to a mutual relationship between two or more things, indicating how they may change together but not providing a solution to a problem.