instruction:
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.
question:
Sentence1: Running water is better able to dissolve oxygen and nutrients than standing water. 
Sentence2: Oxygen and nutrients dissolve easily in rivers.
answer:
dissolve


question:
Sentence1: Mating is generally preceded by courtship. 
Sentence2: Mating is generally similar across species.
answer:
Mating


question:
Sentence1: Sharks breathe using gills. 
Sentence2: sharks convert oxygen with gills.
answer:

Sharks