英语语法分析

This is one of the reasons why some males birds have exotic plumes, why elk carry hefty antlers , and why male fiddler crabs have such large claws.

这就是为什么一些雄鸟长着充满异国情调的羽毛，为什么麋鹿拥有巨大的鹿角，为什么雄性招潮蟹有这么大的爪子的原因之一。

Most volcanoes that occur in the interiors of plates are believed to be produced by mantle plumes, columns of molten rock that rise from deep within the mantle.

人们认为，大多数发生在板块内部的火山爆发都是由地幔柱造成的，地幔柱是指从地幔深处涌出的熔岩柱体。

The plumes apparently originate at great depths, perhaps as deep as the boundary between the core and the mantle, and many have been active for a very long time.

这些地幔柱显然起源于很深的地方，可能深至地核和地幔之间的边界，而且许多都已经活跃了很长时间。