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: gills are used for breathing water by aquatic animals. 
Sentence2: gills are used for breathing water by sharks.
are

Sentence1: Basically the process is pretty simple. 
Sentence2: All cells share some of the same structures and simple processes.
process

Sentence1: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Chloroplasts manufacture nitrogen.

Nitrogen