If there are no truly non-venomous snakes, were the so-called non-venomous snakes, like constrictors and pythons, were they venomous at some point in their evolution?

如果没有真正的无毒蛇，那些所谓的无毒蛇，比如蟒蛇和巨蟒，在它们进化过程中的某个阶段是有毒的吗？

youdao

"Their evolution has never been idle," he says, and presumably never will be.

“过去羽毛的进化绝不是无用的，”他说，而且估计将来也绝不会无用。

youdao

“Their evolution has never been idle, ” he says, and presumably never will be.

“过去羽毛的进化绝不是无用的，”他说，而且估计将来也绝不会无用。

youdao

Here's a little video clip that I'd like to show you that talks about evolution and how humans have evolved in relationship to their food.

接下来我们看段视频,主要讲述了生物演化,还有人类和食物之间的演化关系

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Ellison sees Brazilian equity markets as having gone through two distinct phases in their evolution.

FORBES: Brazilian Equity Market Correction Is 'Healthy,' IPO Expert Says

He will be hands-on with a bunch of these companies through their evolution in these markets.

FORBES: Is Larry Summers Andreessen Horowitz's Kiss of Death?

"History, for all people, is a necessary part of their evolution and their growing process, " he said.

CNN: STORY HIGHLIGHTS