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: Polygenic inheritance Polygenic traits are controlled by an unknown number of genes. 
Sentence2: Skin color is inherited from a number of genes.
[A]: genes


[Q]: Sentence1: Mollusks are invertebrates such as the common snail. 
Sentence2: snails have no backbone.
[A]: snail


[Q]: Sentence1: Montana's wolves are gray wolves, also known as timber wolves. 
Sentence2: Montana has howling.
[A]:
Montana's