instruction:
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.
question:
Evidence of organisms that lived on Earth a long time ago would most likely be found in  
 (A) crystals. (B) lava. (C) sedimentary rock. (D) metamorphic rock.
answer:
C


question:
Sir Isaac Newton stated that every object in the universe attracts matter. The attraction depends on the mass of an object and the distance between the objects. What type of force did Newton describe?  
 (A) centripetal force (B) generalized force (C) centrifugal force (D) gravitational force
answer:
D


question:
Which human body system attacks viruses and bacteria once they have invaded the body?  
 (A) circulatory (B) endocrine (C) digestive (D) immune
answer:

D