单选题
By "physical environment" (Line 2, Paragraph 2), the writer means such elements as ______.
【正确答案】
D
【答案解析】“elements such as temperature，moisture，humidity，pressure，energy use，vibration， light，motion，radiation，gas，and chemicals”中有气体，所以选D。本题也属于细节题，只要回到原文找到正确的对应就可以了。