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.

Sentence1: Polygenic inheritance Polygenic traits are controlled by an unknown number of genes. 
Sentence2: Skin color is inherited from a number of genes.
genes

Sentence1: cell division often causes growth. 
Sentence2: Cell division leads to reproduction.
cell

Sentence1: Endocrine hormones travel throughout the body in the blood. 
Sentence2: For the tourists, there are many places to travel.

travel