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: An example of a cartilaginous fish is a shark. 
Sentence2: jaws make sharks excellent predators.
[A]: shark


[Q]: Sentence1: Cells are programmed to divide only a set number of times. 
Sentence2: Cells reproduce asexually, by dividing.
[A]: divide


[Q]: Sentence1: recycling reduces the resources needed to make something. 
Sentence2: Reuse is the best form of recycling.
[A]:
recycling