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: Ejaculation allows males to reproduce. 
Sentence2: propelling sperm from the epididymes allows males to reproduce.
[A]: allows


[Q]: Sentence1: Every photograph is produced by a camera. 
Sentence2: Photographers record images.
[A]: photograph


[Q]: Sentence1: Oil is less dense than water. 
Sentence2: water sinks in oil because of gravity.
[A]:
Oil