Correct Answer: A

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction, only rearranged. This principle implies that the total amount of matter before and after a chemical reaction must remain constant, supporting the correct answer choice A. Choice B is incorrect because the total amount of matter does not increase in a chemical reaction; it is conserved. Choice C is incorrect as the total amount of matter does not decrease in a chemical reaction; it is conserved. Choice D is incorrect since the conservation of energy is a different principle and does not directly relate to the total amount of matter in a chemical reaction.

Correct Answer: A

Rationale: The correct answer is A, Folliculitis. Folliculitis is the medical term for the inflammation of hair follicles, which can be caused by ingrown hairs. Hirsutism refers to excessive hair growth, pseudofolliculitis barbae is a condition where shaving causes ingrown hairs, and alopecia is hair loss. Therefore, choices B, C, and D are incorrect as they do not specifically refer to ingrown hairs.

Correct Answer: B

Rationale: The correct answer is B, cerebrospinal fluid. Cerebrospinal fluid acts as a shock absorber, protecting the brain from impact and providing nutrients to brain cells. Meninges are the three protective layers of tissue that surround the brain and spinal cord. Dura mater and arachnoid mater are specific layers of the meninges, not the fluid-filled sacs that cushion the brain.

Correct Answer: A

Rationale: When a wave passes from one medium to another with the same speed, its frequency remains unchanged. Frequency is a characteristic of the source of the wave and does not depend on the medium through which the wave is traveling. Wavelength and speed of the wave can change when passing from one medium to another, but frequency remains constant. This is because the frequency of a wave is determined by the source that produces it, and as long as the speed remains constant, the frequency will not be altered. Amplitude, on the other hand, can change based on factors like energy loss or gain, but it is not a property that remains constant when a wave moves between different mediums with the same speed. Speed, although important for the wave's propagation, is not the property that remains unchanged when the wave transitions between mediums with the same speed. Therefore, the correct answer is frequency.

Correct Answer: A

Rationale: The table is much heavier than the book, so it requires a much larger force to accelerate it. The book is lighter and easier to move, so the force applied to it causes it to move without significantly affecting the table due to the table's greater mass. Newton's third law states that for every action, there is an equal and opposite reaction. In this case, the force exerted on the book by the table is countered by an equal force exerted on the table by the book, but the table's greater mass resists movement. Choice B is incorrect because the forces are equal and opposite, acting in the same direction. Choice C is incorrect as the surface area does not affect the movement of the table in this scenario. Therefore, the correct answer is A, as the table's greater mass prevents it from moving easily when a force is applied.