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.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.

i believe the answer is true.