You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Which force produces energy as heat?  
 (A) pull (B) gravity (C) friction (D) magnetic
C

A meteoroid becomes a meteorite when it  
 (A) impacts the surface of a planet. (B) encounters the atmosphere of a planet. (C) makes a complete orbit around a planet. (D) starts to burn up in the atmosphere of a planet.
A

Asbestos fibers cause a cancer called mesothelioma in humans. The fibers kill cells that line lung tissue by causing programmed-cell death. When cells die this way, they release a chemical, HMG1, which causes an inflammatory response in other cells. During this inflammatory response, cells release chemicals that promote tumor growth. What conclusion can you draw about the chemicals released in the inflammatory response?  
 (A) They decrease the amount of HMG1 in a feedback loop. (B) They increase the amount of HMG1 in a feedback loop. (C) They disrupt the normal circadian rhythms. (D) They disrupt the normal cell cycle.

D