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


[Q]: Sentence1: nectar is used for attracting pollinators by plants. 
Sentence2: butterflies pollinate plants.
[A]: plants


[Q]: Sentence1: a plant requires nutrients to grow. 
Sentence2: elms require nutrients to grow.
[A]:
grow