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What effect does a catalyst have on a chemical reaction?
- A. It speeds up the reaction.
- B. It slows down the reaction.
- C. It makes a reaction go in reverse.
- D. It prevents a reaction from taking place.
Correct Answer: A
Rationale: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by providing an alternate pathway for the reaction to occur, lowering the activation energy needed for the reaction to proceed. As a result, more reactant molecules can overcome this energy barrier and participate in the reaction, leading to a faster overall reaction rate. This explanation contradicts choices B, C, and D as a catalyst does not slow down, reverse, or prevent a reaction; instead, it accelerates the reaction by facilitating a more efficient route for the reaction to take place. Therefore, the correct answer is that a catalyst speeds up the reaction.
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When defending a scientific argument, which technique is most effective?
- A. Citing other scientists who agree with your argument.
- B. Showing the results of scientific experiments that support your argument.
- C. Describing your scientific credentials, education, and past accomplishments.
- D. Pointing out that no one has come up with a proven alternative explanation.
Correct Answer: B
Rationale: The most effective technique when defending a scientific argument is to show the results of scientific experiments that support your argument. In the realm of science, evidence-based support is crucial. By presenting concrete data and experimental results, you provide a convincing and reliable foundation for your argument. This method allows others to review, replicate, and verify the findings, thus strengthening the credibility of your position. Choices A, C, and D are not as effective as choice B because citing other scientists who agree with your argument (Choice A) may not carry the same weight as empirical evidence, describing your scientific credentials, education, and past accomplishments (Choice C) may not directly address the validity of your argument, and pointing out that no one has come up with a proven alternative explanation (Choice D) does not provide direct evidence supporting your argument.
What is the control, if any, in this experiment?
- A. There is no control in this experiment
- B. The control is the water
- C. The control is the diet soda
- D. The control is the amount of sunlight provided to the plants
Correct Answer: B
Rationale: The correct answer is B: 'The control is the water.' In a scientific experiment, the control group is used as a baseline comparison to evaluate the effects of the variables being tested. Here, the water serves as the control group against which the effects of other substances like diet soda or different amounts of sunlight can be compared. Choice A is incorrect as every experiment should have a control group for comparison. Choice C and D are incorrect as they are not the standard control in this scenario.
Enzymes are ________ molecules that serve as _______ for certain biological reactions.
- A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
- B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
- C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
- D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.
Correct Answer: D
Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.
Which of the following areas has the least amount of sweat glands?
- A. Back
- B. Palms
- C. Axilla
- D. Forehead
Correct Answer: B
Rationale: The correct answer is B - Palms. The palms have the least amount of sweat glands compared to the other options listed. The back, axilla (armpits), and forehead are all areas with a higher concentration of sweat glands in the body. The palms have fewer sweat glands to minimize water loss and maintain a better grip for activities requiring precise and controlled movement. The back, axilla, and forehead have more sweat glands to assist in thermoregulation and cooling of the body, while the palms have fewer sweat glands for functional reasons related to grip and dexterity.
Which organ system is most responsible for maintaining control of body temperature?
- A. The skeletal system.
- B. The circulatory system.
- C. The immune system.
- D. The muscular system.
Correct Answer: B
Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.