In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant.

Greenhouse gases are released into the air by human activities. The earth changes energy from the sun into heat. Heat rises from the ground. Greenhouse gas molecules in the atmosphere prevent the heat from going into space. The temperature of the earth increases. The temperature continues to rise and melts the polar ice caps. The temperature rises even faster.
greenhouse gas ,air ,earth ,energy from sun ,heat ,greenhouse gas molecules ,polar ice cap

Some of the rock in the ground is made of limestone. Over long periods of time rain can hit the limestone. And cause a acidic reaction. The limestone will slowly disintegrate. A large gap with be where the limestone was. Result in the cave.
rain ,limestone ,gap; cave

Fault lines appear underground. The fault lines grow over time. The rocks on each side of the fault lines rub against the rocks on the other side of the fault line. The rocks put pressure on each other. The rocks break from the pressure. The breaking of the rocks releases a lot of energy. The energy causes seismic waves. The seismic waves make the earth shake.
fault lines ,pressure ,rocks ,energy ,seismic waves