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: Streams may start with runoff or water seeping out of a spring. 
Sentence2: streams may start with runoff or h2o seeping out of a spring.

A: Streams
****
Q: Sentence1: Aerosols of uranium dioxide can travel a long distance. 
Sentence2: aerosols of uranium dioxide can migrate.

A:
Aerosols
****