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: Sharpening a pencil and tearing paper are examples of physical changes. Which statement describes why these are physical changes?  
 (A) There is a change in how the objects are used. (B) There is a change in the appearance of the objects. (C) There is a change in the materials from which the objects are made. (D) There is a change in both the appearance of the objects and the materials from which they are made.

SOLUTION: B

PROBLEM: Joann repeatedly overfed the fish in the pond behind her house. The nitrates from the excess food contributed to an overgrowth of algae. To correct the problem, Joann added more plants to the pond. How will adding more plants help?  
 (A) The plants make the pond look beautiful. (B) The plants will camouflage the green algae. (C) The plants will compete with algae for nutrients. (D) The plants will provide all the food for the fish.

SOLUTION: C

PROBLEM: Which pair of items will repel each other?  
 (A) a positively-charged wool sock and a neutral plastic bag (B) a neutral cotton sweater and a negatively-charged plastic pellet (C) a negatively-charged balloon and a positively-charged piece of paper (D) a negatively-charged plastic strip and a negatively-charged piece of cloth

SOLUTION:
D