Over millions of years, heat and pressure have converted the remains of ancient forests to fossil fuels. The burning of these fossil fuels has a direct effect on which of the following natural cycles?

The carbon cycle

Explanation:

The burning of fossil fuels returns the carbon (of which they were made of) back into the atmosphere.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.