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.

A student conducts an investigation. In order to make a valid conclusion, she must  
 (A) have a testable hypothesis. (B) place the data in a graph. (C) use the best technology. (D) test multiple variables.
A

The greatest amount of diversity can be found among which type of organism?  
 (A) plants (B) animals (C) bacteria (D) fungi
C

A student observes cells in an object by using a microscope. The student thinks that the object was part of a living thing. Which statement explains why cell theory can be used to support the student's thinking?  
 (A) Cell theory was developed using a microscope. (B) Cell theory was developed to study living things. (C) Cell theory states that all living things are made of cells. (D) Cell theory states that scientists may classify things as living or nonliving.

C