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: heating an egg causes a chemical reaction in the egg. 
Sentence2: Insects hatch from eggs.
egg

Sentence1: Coral reefs are made up of the accumulated exoskeletons of the coral polyp. 
Sentence2: coral polyps form reefs.
polyp

Sentence1: Chemical weathering causes chemical changes in the minerals of a rock. 
Sentence2: moss causes chemical changes in the minerals of a rock.

changes