—I think teenagers should be allowed to make their own decisions when they have problems at school.
—_______. They're not calm enough, after all.
A:I agree
B:I disagree
C:I think so
D:I'm sure
①山东 ②山西 ③河北 ④河南
保护生物的____环境,保护生态系统的____,是保护生物多样性的根本措施.