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.

Ex Input:
Sentence1: Skin color is another polygenic trait. 
Sentence2: Skin color is influenced by multiple genes.

Ex Output:
Skin


Ex Input:
Sentence1: Heterotrophs get food by eating other living things. 
Sentence2: fish eat other living things.

Ex Output:
living


Ex Input:
Sentence1: plant requires seed dispersal for reproduction. 
Sentence2: Rodents as seed consumers and seed dispersers.

Ex Output:

dispersal