单选题
As a defense against air-pollution damage, many plants and animals ______ a substance to absorb harmful chemicals.
【正确答案】
B
【答案解析】解析：release vt.释放(囚犯、热、能量等)；发布(消息)；放开，松开(release a prisoner；release energy：release the brake：release news to the public：release sb．from his obligations)。relieve vt．减轻，解除；救济。dismiss vt．解散，遣散；免职，解雇，开除：(认为不重要而)不再考虑。discard vt．丢弃，抛弃。