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.

Scientists found fish fossils in the desert. What do the fossils tell about this environment when the fish were alive?  
 (A) There was a forest with large trees. (B) There were lakes with water plants. (C) There were mountains with glaciers. (D) There was a desert with large rocks.
B

Humans use both renewable and nonrenewable resources. Which human activity uses a nonrenewable resource?  
 (A) building houses with wood (B) using natural gas to heat homes (C) using solar energy to power lights (D) producing electricity from flowing water
B

The element cesium, Cs, is an alkali metal. Which chemical formula represents a cesium compound that is likely to exist?  
 (A) CsCl (B) CsCl_{2} (C) CsO (D) CsO_{2}

A