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: Cnidarians have a hydrostatic skeleton. 
Sentence2: Jellyfish have a hydrostatic skeleton.

A: hydrostatic
****
Q: Sentence1: camouflage is used for protection by prey against predators. 
Sentence2: blending is used for protection.

A: protection
****
Q: Sentence1: seasons cause change to the environment. 
Sentence2: weather cause change to the environment.

A:
cause
****