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: Running water is better able to dissolve oxygen and nutrients than standing water. 
Sentence2: Oxygen and nutrients dissolve easily in rivers.

A: dissolve
****
Q: Sentence1: Ejaculation allows males to reproduce. 
Sentence2: propelling sperm from the epididymes allows males to reproduce.

A: allows
****
Q: Sentence1: Populations are large groups of individuals. 
Sentence2: bottleneck effect occurs when large groups of individuals suddenly gets much smaller.

A:
groups
****