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: In 1971, the bones of an extinct flying dinosaur were discovered. This kind of discovery helps everyone learn more about  
 (A) impact of humans on Earth. (B) effect of gravity on animals. (C) history of animal species on Earth. (D) likelihood that dinosaurs will reappear.

Answer: C


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

Answer: D


Question: A student sees many plants around a pond. The student can determine which plants are nonvascular by  
 (A) observing if they lack true stems, roots, or leaves (B) examining the plants for spores (C) counting the number of leaves on each stalk (D) noticing if the plants are near rocks

Answer:
A