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.
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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: A student plans to grow algal colonies in solutions with different concentrations of liquid fertilizer. Which is a clear and testable hypothesis to guide this investigation?  
 (A) Algae like fertilizer. (B) Fertilizer is good for algae. (C) Fertilizer improves the genetic traits of algae. (D) Algal growth rate increases with fertilizer concentration.

Answer: D


Question: Barney is a cat. Which trait was made by his environment?  
 (A) Barney has a long tail. (B) Barney has brown eyes. (C) Barney has a pink tongue. (D) Barney has a scar on his ear.

Answer:
D