Question

Question #f53de

Answer 1

All life shares a common ancestor.

Explanation:

Crocodiles must share a common ancestor with birds, dolphins, and dogs because all are alive. That being said, the animals you mentioned are mostly in different categories. A crocodile is a reptile, birds are their own category, while dolphins and dogs are mammals.

We can use this information to hypothesize how long ago these animals' last common ancestor lived. Dolphins and dogs would be most related because both are mammals. Crocodiles and birds are in two categories that are close to each other. So it would go birds, and then dogs and dolphins in terms of how long ago each shared a common ancestor with crocodiles.