During the period, jawless fishes were the first vertebrates to leave fossil evidence.

How do adaptation affect a species?

Number and variety of living organism; includes genetic, species, and ecological types

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere