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: when a hurricane moves over land , that hurricane will decrease in strength. 
Sentence2: Hurricanes form over the warm tropical water in ocean and die down when they move over land.
land

Sentence1: Muscles can only contract. 
Sentence2: Contraction is a type of movement.
contract

Sentence1: All bears are covered with heavy fur. 
Sentence2: bears can keep warm.

bears