We learn from the text that p…——2009 高考英语第 49 题答案解析

【解答】
$We learn from the text that plants communicate with each other by______.$
A. making some sounds B. waving their leaves
C. producing some chemicals D. sending out electronic signals
【解析】细节理解题。根据开篇第二句“produce volatile compounds,
chemicals”，【答案】Ｃ。