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.
Q: The air is cold. Water is in the air. The water forms tiny ice crystals. The ice crystals collide with each other. The ice crystals stick to each other. The ice crystals get bigger as more of them stick together. The ice crystals get too heavy to be in the air. The ice crystals become snowflakes. The snow flakes fall to the ground as snow.
A:
water ,ice crystals ,snow flakes; snowflakes; snow