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.

[EX Q]: Sentence1: Some birds are pollinators that co-evolved with plants. 
Sentence2: insects pollinate plants.
[EX A]: plants

[EX Q]: Sentence1: erosion causes a river to become deeper and wider. 
Sentence2: On the contrary, the NILE is the longest river in Africa.
[EX A]: river

[EX Q]: Sentence1: webbed feet are used for moving faster through water by aquatic animals. 
Sentence2: Ducks can move fast through water.
[EX A]:
faster