instruction:
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. 
question:
When water freezes it becomes 10% bigger, or takes up 10% more space. As water expands it puts great pressure on the walls of anything containing it, including any rocks which happen to be surrounding it. The force of the pressure exerted on the rock surrounding it is enough to wedge the walls of the crack farther apart, thus expanding and deepening the crack. Clay expends when wet like ice does. This causes rock to break apart. Some plants like mosses and lichens are capable of growing without soil on bare rock. When they do this their roots penetrate pores and crevices and cause rocks to split apart as the roots force their way down through the rocks. 
answer:
crack ,rock 


question:
Techtonic plates in the earths crust move. Movement creates fissures. Upheavals in the crust. Fissures allow lava to erupt into volcanoes at the surface. Volcanoes erupt, accumulating lava, forming mountains. Upheavals in the crust become their own mountains. 
answer:
tectonic plates ,fissures ,upheavals in the crust ,lava ,volcanoes ,mountains ,their own mountains 


question:
Food enters the mouth. Food mixes with saliva. Food is swallowed. Enzymes in the stomach break down the food. The food moves to the small intestine. Hormones from the pancreas move to the small intestine. The hormones create the amount of sugar in the blood from the food. The sugar in the blood travels to the body. The sugar provides energy for the muscles. 
answer:

food ,broken down food ,sugar ,energy