TASK DEFINITION: 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.
PROBLEM: Which of these elements is found in the greatest amount in organisms?  
 (A) carbon (B) iron (C) lead (D) neon

SOLUTION: A

PROBLEM: Which form of energy are x rays and ultraviolet light?  
 (A) nuclear (B) heat (C) electromagnetic (D) chemical

SOLUTION: C

PROBLEM: On the Galapagos Islands, an iguana that lives in the water is most likely able to survive without competition from an iguana that lives on land because it  
 (A) swims faster. (B) has a larger body. (C) has a tougher scaly skin. (D) has a different food source.

SOLUTION:
D