Ferns, such as the one in the picture, can be found today. They are usually found
growing in warmer climates. However, fossils of ferns have been found in places with
cold climates where it often snows today. What can we conclude about the places
where the fossils of ferns have been found?

A. Ferns used to live in cold climates.

B. These places once had a warmer climate.

C. Someone tried to grow ferns in cold climates.

D. These places once had a colder climate.