What is the relationship between work and the displacement of an object?

Correct Answer: B

Rationale: Work is directly proportional to displacement. In physics, work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force. Therefore, work is directly proportional to displacement. Choice A is incorrect because work is dependent on both force and displacement. Choice C is incorrect because work is not inversely proportional to displacement; it is directly proportional. Choice D is incorrect because work is indeed related to displacement, as described in the definition of work in physics.

Correct Answer: A

Rationale: The correct answer is that the kinetic energy remains the same. Kinetic energy is directly proportional to the mass of an object and the square of its velocity. When the mass is doubled, the kinetic energy would increase if the velocity remains constant. However, in this question, only the mass is mentioned, not the velocity. Therefore, when the mass is doubled, the kinetic energy remains the same as long as the velocity remains constant. Choices B, C, and D are incorrect because they incorrectly suggest changes in kinetic energy that do not accurately reflect the relationship between mass and kinetic energy described in the question.

Correct Answer: C

Rationale: Oleic acid is an example of an unsaturated fatty acid because it contains one or more double bonds in its hydrocarbon chain, leading to kinks in the chain structure. This unsaturation gives it a lower melting point compared to saturated fatty acids. Stearic acid (A), Palmitic acid (B), and Butyric acid (D) are examples of saturated fatty acids as they do not contain any double bonds in their hydrocarbon chains, leading to a straight structure and higher melting points.

Correct Answer: A

Rationale: The liver is the main organ responsible for producing bile. Bile, a greenish-yellow fluid, is produced by the liver and stored in the gallbladder. Its primary function is to aid in the digestion and absorption of fats in the small intestine. When needed, the gallbladder releases bile into the small intestine to facilitate fat digestion. The pancreas produces digestive enzymes and insulin, not bile, making choice C incorrect. The stomach's primary role is to digest food through gastric juice secretion, making choice D incorrect. Therefore, the correct answer is the liver, as it is the main organ responsible for bile production.

Correct Answer: B

Rationale: The kidneys play a crucial role in regulating blood pressure through various mechanisms. One of the key ways the kidneys regulate blood pressure is by controlling the volume of blood in the body. They do this by adjusting the amount of water and sodium excreted in the urine. The renin-angiotensin-aldosterone system, primarily controlled by the kidneys, also plays a significant role in blood pressure regulation. This system helps to maintain blood pressure by regulating blood volume and systemic vascular resistance. While the heart, adrenal glands, and pituitary gland are involved in various aspects of the cardiovascular and endocrine systems, the kidneys are the main organ responsible for regulating blood pressure.