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.

Q: Sentence1: adding salt to a solid decreases the freezing point of that solid. 
Sentence2: Water density decreases with temperature and increases with salt content.

A: decreases
****
Q: Sentence1: hurricanes convert heat energy into mechanical energy. 
Sentence2: Hurricanes use heat to move objects.

A: hurricanes
****
Q: Sentence1: Biologists use microscopes to study things that are too small to be seen with the unaided eye. 
Sentence2: Biologists study small things that can't normally be seen with an unaided eye.

A:
eye
****