Question

read the information before answering the question. what does the presence of a bone structure in a whales tail signify? whales had hind legs when they were large land mammals. whales were once bird - like creatures. (the last option is partially shown: whales used to have extra fins for navigation)

Explanation:

The bone structure in a whale's tail is a vestigial structure. Vestigial structures are remnants of organs or structures that had a function in an early ancestor. Whales are mammals, and the presence of bone structures related to hind legs (even in the tail region) supports the idea that whales evolved from land - dwelling mammals that had hind legs. The option "Whales were once bird - like creatures" is incorrect as whales are mammals, not related to birds in that way, and the bone structure in the tail is not related to being bird - like. The idea of extra fins for navigation is also not supported by the concept of vestigial hind - leg - related bone structures.

Answer:

A. Whales had hind legs when they were large land mammals.