When might you have been able to see a human (Homo sapien) hunt down a wooly mammoth, or have to defend him/herself from a saber toothed cat? Write it as: Era > Period—Epoch
Aspa

Coal begins to form when plants die in a swampy area is the correct statement.

Explanation:

Coal was shaped once huge amounts of the plant died and fell into the swamps they grew in. This happened within the Carboniferous period. Vast mats of wet material were shaped that resisted decay as a result of there was a little chemical element there. Hence, after billions of years, this deposition of dead plants from coal.