题目

Want to help fight global warming? Take off your tie, says the Italian health ministry. It has urged employers to let their staff dress casually at work in the summer so that the air conditioning can be turned down.“Taking your tie off immediately lowers the body temperature by 2 or 3 degrees centigrade,” the ministry said in a statement.“Allowing a more sensible use of air conditioning brings about electricity savings and protects the environment.”It called on all public and private offices to let employees wear no tie during heat waves like the one that has brought Africa-l下列关于隔离的叙述，不正确的是(　　) A.阻止了种群间基因的交流 B.物种的形成都必定先经过长期的地理隔离 C.遗传组成上的差异是产生生殖隔离的根本原因 D.多倍体植物的形成不需要经过地理隔离