Answer:
A hot and very swampy environment, full of plants and stagnant water
Step-by-step explanation:
This photograph shows a mountainside with exposed coal beds interlayered with sandstone and shale. The coal was formed as debris from the landscape and was gradually buried 4 to 10 km deep over a very long period of time.
Under a hot conditions, and very swampy environment, full of plants and stagnant water are the coal beds formed from.