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: Plants growing in a pond release a gas that fish need to survive. Which gas do the plants release that fish use?  
 (A) helium (B) hydrogen (C) nitrogen (D) oxygen

Answer: D


Question: Which is a fact rather than an opinion about earthquakes?  
 (A) Earthquakes occur along fault lines. (B) Earthquakes are worse than hurricanes. (C) Earthquakes are bad for all local businesses. (D) Earthquakes always cause major damage to homes.

Answer: A


Question: When an iron nail wrapped in a copper wire is attached to a circuit, it forms  
 (A) a battery. (B) an engine. (C) an insulator. (D) an electromagnet.

Answer:
D


