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A car is accelerating down a hill. Which of the following forces is NOT acting on the car?
- A. Gravitational force
- B. Normal force from the road
- C. Air resistance
- D. The car's engine force
Correct Answer: B
Rationale: When a car is accelerating down a hill, the normal force from the road is not acting on the car. The normal force is the force exerted by a surface to support the weight of an object resting on it. As the car moves downhill, the normal force decreases since the road is no longer pushing back against the car's weight due to the downhill motion. Gravitational force pulls the car downhill, air resistance opposes the car's motion, and the car's engine force propels it forward. Therefore, the correct answer is B, as the normal force from the road is not acting on the car while it accelerates downhill.
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What is the primary function of coronary arteries?
- A. Delivering oxygenated blood throughout the body.
- B. Supplying oxygenated blood to the heart muscle itself.
- C. Carrying deoxygenated blood back to the heart.
- D. Regulating blood pressure through vasoconstriction and vasodilation.
Correct Answer: B
Rationale: The primary function of coronary arteries is to supply oxygenated blood to the heart muscle itself. The heart is a muscle that needs a constant supply of oxygen and nutrients to function properly. Coronary arteries branch off the aorta and specifically deliver oxygenated blood to the heart muscle, ensuring its proper function. Choice A is incorrect because coronary arteries do not deliver blood throughout the entire body but specifically to the heart. Choice C is incorrect as coronary arteries carry oxygenated blood away from the heart. Choice D is incorrect as the primary function of the coronary arteries is not to regulate blood pressure but rather to provide oxygenated blood to the heart muscle.
Which of the following is an example of a polymer?
- A. Methane
- B. Ethanol
- C. Polyethylene
- D. Acetic acid
Correct Answer: C
Rationale: The correct answer is C, Polyethylene. Polyethylene is a polymer composed of a large number of repeating ethylene units linked together, forming a long-chain molecule, characteristic of polymers. Methane, ethanol, and acetic acid are small organic molecules that do not demonstrate the repeating unit structure typical of polymers. Therefore, they are not examples of polymers.
In a food chain, which trophic level captures energy from the sun?
- A. Decomposers
- B. Carnivores
- C. Producers
- D. Omnivores
Correct Answer: C
Rationale: Producers, such as plants, algae, and some bacteria, are the organisms in a food chain that capture energy from the sun through the process of photosynthesis. They convert sunlight into chemical energy, which is then passed on to other organisms in the food chain. Producers are at the base of the food chain and form the foundation for all other trophic levels to obtain energy. Decomposers (option A) break down organic matter, carnivores (option B) consume other animals, and omnivores (option D) consume both plants and animals, but they do not directly capture energy from the sun.
Which of the following is NOT a component of the body's innate immune response?
- A. Physical barriers like skin and mucous membranes
- B. Phagocytes that engulf and destroy pathogens
- C. Inflammatory response to isolate and contain infection
- D. Production of antibodies specific to a particular pathogen
Correct Answer: D
Rationale: The production of antibodies specific to a particular pathogen is a function of the adaptive immune response, not the innate immune response. Innate immunity involves nonspecific defense mechanisms like physical barriers, phagocytes, and inflammation, which provide immediate protection against pathogens without prior exposure. Antibody production is a characteristic of adaptive immunity, where the body generates specific antibodies in response to encountering a pathogen for the first time. Therefore, option D is the correct answer as it does not align with the immediate and nonspecific nature of the innate immune response.
When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), what type of reaction occurs?
- A. Combustion
- B. Double displacement
- C. Decomposition
- D. Synthesis
Correct Answer: B
Rationale: When baking soda (sodium bicarbonate) reacts with vinegar (acetic acid), a double displacement reaction occurs. In this reaction, the positive ions in baking soda switch places with the positive ions in vinegar to form water, carbon dioxide, and a salt. Combustion involves a reaction with oxygen to produce heat and light energy. Decomposition is the breakdown of a compound into simpler substances, which is not the case in the given reaction. Synthesis is the combination of substances to form a more complex compound, which is also not the type of reaction observed when baking soda and vinegar react.