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

SOLUTION: freezing

PROBLEM: Sentence1: Ions are atoms or groups of atoms that carry a positive or negative electrical charge. 
Sentence2: An ion is formed after a neutral atom loses an electron.

SOLUTION: Ions

PROBLEM: Sentence1: sweat is used for adjusting to hot temperatures by some animals. 
Sentence2: High humidity interferes with evaporation of the sweat.

SOLUTION:
sweat