Why are some volcanoes explosive and others not?

It depends on the composition of each volcano's magma. Some volcanoes erupted with loud explosion while the other only spurt out the lava peacefully. There's also some volcanoes which not erupting but it was considered as an active volcano and that's all depends on the composition of the magma. (hope it helpful)

D, the answer is letter d. because even though fossil fuels take a very long time to form, they do form in the ground just like coal and others.

The answer is the magnetosphere.