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: Muscles can only contract. 
Sentence2: Contraction is a type of movement.
contract

Sentence1: Coral Reefs Coral reefs are widely distributed in warm shallow waters. 
Sentence2: warm shallow waters provide food and shelter to many ocean organisms.
shallow

Sentence1: braking can cause skidding. 
Sentence2: Harsh braking increases the wear of the brakes and the tyres.

braking