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: All sharks are predators. 
Sentence2: hiding can be used for avoiding sharks.

A: sharks
****
Q: Sentence1: June Summer Triangle Three bright stars light up the summer sky. 
Sentence2: Nuclear reactions in stars cause them to brighten up the summer sky.

A: bright
****
Q: Sentence1: Immediate reporting is also required for diseases caused by Category A Bioterrorism agents. 
Sentence2: spread of disease is another potential threat in the environment.

A:
diseases
****