logo - 刷刷题
下载APP
【多选题】

白垩纪末大灭绝可能的原因( )。

A.
火山喷发
B.
外星撞击
C.
海水变清澈
D.
气候变化
举报
题目标签:白垩纪灭绝
参考答案:
参考解析:
.
刷刷题刷刷变学霸
举一反三

【单选题】白垩纪属于( )

A.
古生代早期
B.
古生代晚期
C.
中生代
D.
新生代

【单选题】Many people feel that human beings are responsible for the disappearance of some other animal species. While we may have hastened the disappearance of some, abundant evidence suggests mankind has had ...

A.
Human beings have hastened the disappearance of some.
B.
There was mass extinction long before humanity's time on Earth.
C.
Human beings'activities have had great impact on the earth.
D.
Many species have extinct since the human race came into being.