instruction:
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:
Campers shouted toward a canyon wall. What characteristic of sound best explains why the campers heard an echo?  
 (A) Sound waves traveled slowly down the canyon. (B) Sound waves were absorbed by the canyon wall. (C) Sound waves reflected off the canyon wall. (D) Sound waves were refracted around the canyon.
answer:
C


question:
Marta studied different forms of energy. Which two types of energy travel in waves?  
 (A) light and sound (B) electrical and sound (C) chemical and light (D) chemical and electrical
answer:
A


question:
The United States government limits the use of certain pesticides through laws passed in the Endangered Species Protection Program. Which is the most likely reason to enforce laws that limit pesticide use?  
 (A) Some pesticides are expensive. (B) Some pesticides fail to control insects. (C) Some pesticides give off foul odors. (D) Some pesticides can harm non-targeted species.
answer:

D