TASK DEFINITION: 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.
PROBLEM: If an ecosystem's balance is disturbed by a volcanic eruption, what will most likely occur?  
 (A) The ecosystem will not change from its original state. (B) The ecosystem will eventually become balanced again. (C) The consumers in the ecosystem will begin to consume carbon dioxide. (D) The consumers in the ecosystem will begin to produce more oxygen.

SOLUTION: B

PROBLEM: In an experiment studying phototropism, students grew bean plants in labeled cardboard milk cartons. Afterward, the plants and soil were properly discarded. Which instruction line BEST conserves the remaining resources?  
 (A) recycle the markers, reuse the milk cartons (B) reuse the markers, discard the milk cartons (C) discard the markers, reuse the milk cartons (D) reuse the markers, recycle the milk cartons

SOLUTION: D

PROBLEM: A sailboat travels 35 km in 5 hr. Which of the following describes the motion of the sailboat?  
 (A) Its momentum is 7 km/hr. (B) Its acceleration is 7 km/hr. (C) Its displacement is 7 km/hr. (D) Its average speed is 7 km/hr.

SOLUTION:
D