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: an animal requires nutrients to grow and heal. 
Sentence2: Microbes can help an animal to grow and heal.
[A]: grow


[Q]: Sentence1: Lymph is a fluid that leaks out of capillaries into spaces between cells. 
Sentence2: Bacteria invade lymph nodes, which swell, creating the buboes.
[A]:
Lymph