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 organisms contribute most to the decomposition of dead organisms?  
 (A) snakes (B) viruses (C) insects (D) bacteria
D

Sharpening a pencil and tearing paper are examples of physical changes. Which statement describes why these are physical changes?  
 (A) There is a change in how the objects are used. (B) There is a change in the appearance of the objects. (C) There is a change in the materials from which the objects are made. (D) There is a change in both the appearance of the objects and the materials from which they are made.
B

A large rock breaks into small pieces within 10 years. Which process is most likely responsible for breaking the large rock into small pieces within 10 years?  
 (A) steady winds blowing throughout the years (B) gentle rain falling during each spring and fall (C) lack of rain falling during a four-year drought (D) water repeatedly freezing and thawing in a crack

D