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: Mollusks are invertebrates such as the common snail. 
Sentence2: snails have no backbone.

A: snail
****
Q: Sentence1: Mammalian predators include the coyote and bobcat. 
Sentence2: a coyote's teeth is important for digestion.

A: coyote
****
Q: Sentence1: Serious side effects resulting from vaccination are extremely rare. 
Sentence2: Vaccination leads to immunity and extremely rarely with serious side effects.

A:
Serious
****