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: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.

A: Earthquakes
****
Q: Sentence1: Leeches are external parasites. 
Sentence2: Leeches live on the surface of their hosts.

A: Leeches
****
Q: Sentence1: Germs can contaminate surfaces and objects around the water. 
Sentence2: Scraping oneself on surfaces or things that have germs may cause infection.

A:
Germs
****