One characteristic of many lamprey but not of hagfishes is

Today, hagfishes and lampreys are recognized as separate clades, primarily because lampreys are true vertebrates, whereas hagfishes are not. A defining feature is the lack of paired lateral appendages (fins). Some of the earliest jawless fishes were the ostracoderms (which translates to “shell-skin”).

Explanation:

Hope this helps. :-) I explained it in the answer.

c.more precipitation,but only when emission levels.

the fossil record provides evidence of a common ancestor to many species.