Choose your answer from: 1). greenhouses 2). staying warm 3). Enzymes 4). earmuffs 5). electricity 6). jackets 7). sweaters 8). exoskeleton
Q: You are presented with the quiz "What is used to protect plants from contracting molecules?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "agreenhouse is used to protect plants from the cold" and "molecules expand with heat and contract with cold". So, what's the best answer to the question?
A:
1).