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 an ecosystem, not all of the energy that is available is used by the organisms. Some energy becomes unavailable before it can be transferred to organisms in the next trophic level. How does the energy most likely become unavailable?  
 (A) The energy is stored as food. (B) The energy is dissipated as heat. (C) The energy is trapped in dead organisms. (D) The energy is moved to another ecosystem.

Answer: B


Question: Energy appears in many forms. What form of energy is lightning?  
 (A) electrical energy (B) mechanical energy (C) magnetic energy (D) sound energy

Answer: A


Question: Which of the following statements best describes how the four planets closest to the Sun are different from the next four planets in our solar system?  
 (A) The four closest planets are more dense. (B) The four closest planets have more moons. (C) The four closest planets have greater diameters. (D) The four closest planets take longer to complete one orbit.

Answer:
A