Asedimentary rock containing a fern fossil was found
what does this tell about the area at the time the rock
was formed?

The area must have been on land

Explanation:

Ferns are vascular plants that produces no seeds but reproduce by their spores. They are usually land dwelling plants. Ferns are numerous flowerless and seedless vascular plants having true roots.

Sedimentary rocks usually form as a result of the accumulation of sediments within basins of their deposition. If one encounters fossils of ferns in sedimentary layer, it implies that the sediments must have been brought from land or the area where the sediments were deposited was on land.

gas

explanation:

smoke is the matter of a gas

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.