Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Sentence1: freezing means changing from a liquid into a solid by reducing heat energy. 
Sentence2: Water freezes into ice when cooled.
freezing

Sentence1: conserving water can be used for survival in a dry environment. 
Sentence2: conserving water can be used for survival in deserts.
conserving

Sentence1: intense heat has a negative impact on an organism. 
Sentence2: skin burning quickly has a negative impact on an organism.

impact