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As a car accelerates from rest, what happens to its kinetic energy and the work done on it?
- A. Both kinetic energy and work done increase.
- B. Kinetic energy increases, but work done remains constant.
- C. Work done increases, but kinetic energy remains constant.
- D. Both kinetic energy and work done remain constant.
Correct Answer: A
Rationale: When a car accelerates from rest, its speed and kinetic energy increase. The work done on the car is what increases its kinetic energy, so both kinetic energy and work done increase simultaneously. Option A is correct because acceleration results in an increase in both kinetic energy and the work done on the car. Option B is incorrect because work done is required to increase kinetic energy during acceleration. Option C is incorrect as work done is directly related to the change in kinetic energy. Option D is incorrect as both kinetic energy and work done increase when the car accelerates.
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How does polarization affect the intensity of light passing through a polarizing filter?
- A. All light passes through regardless of polarization.
- B. Light with the same polarization as the filter passes through, while others are blocked.
- C. Light with higher intensity passes through, while weaker light is blocked.
- D. The intensity is reduced for all light, regardless of polarization.
Correct Answer: B
Rationale: A polarizing filter only allows light waves with a specific orientation (polarization) to pass through while blocking light waves with different orientations. Therefore, light with the same polarization as the filter will pass through, while light with different polarizations will be blocked. This results in a reduction in intensity for light passing through the polarizing filter. Choice A is incorrect because a polarizing filter selectively filters light based on its polarization. Choice C is incorrect as the intensity of light passing through is determined by its polarization, not solely its intensity. Choice D is incorrect because a polarizing filter affects light based on its polarization, not uniformly reducing the intensity for all light passing through.
Which organ produces insulin?
- A. Pancreas
- B. Liver
- C. Stomach
- D. Kidneys
Correct Answer: A
Rationale: Insulin is a hormone that regulates blood sugar levels by facilitating the uptake of glucose into cells for energy production or storage. The pancreas, located behind the stomach, is the organ responsible for producing insulin. Within the pancreas, specialized cells known as beta cells synthesize and secrete insulin in response to changes in blood glucose levels. The liver, although vital for metabolism, does not produce insulin. Similarly, the stomach and kidneys do not play a role in insulin production. Hence, the correct answer is the pancreas.
Bile, a digestive juice, is produced by which organ?
- A. Stomach
- B. Liver
- C. Pancreas
- D. Small intestine
Correct Answer: B
Rationale: Bile is a digestive juice produced by the liver. It is stored in the gallbladder and released into the small intestine to aid in the digestion and absorption of fats. The stomach (Choice A) produces gastric juices, not bile. The pancreas (Choice C) produces digestive enzymes and bicarbonate but not bile. The small intestine (Choice D) is where bile is released to aid in digestion but is not the organ that produces bile.
How can a single gene mutation lead to multiple phenotypes depending on the organism?
- A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
- B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
- C. Genetic drift refers to random changes in allele frequencies within a population.
- D. Gene regulation controls the timing and level of gene expression within an organism.
Correct Answer: A
Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.
What property of a substance measures the amount of matter per unit volume?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: C
Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of an object by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Therefore, in this context, density is the correct answer as it specifically relates to the concentration of matter within a given volume.