In the sentence, the writer describes the central idea. A general topic. A supporting detail. The author’s purpose.

Snakes, dogs, and humans have a vertebral column. snakes and dogs have tails, and humans have vestigial tailbones. dogs and humans have limbs, but snakes do not. most reptiles lay eggs, but a few give birth to live young. what do these structures suggest about the evolutionary pattern between the three organisms? 1. snakes and dogs are more closely related than snakes and humans. 2. snakes and humans are more closely related than humans and dogs. 3. dogs and humans are more closely related than snakes and humans. 4. dogs, snakes, and humans share a common ancestor. 5. the early ancestor of snakes and dogs is the same, and the early ancestor of humans is different.