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: a mutation in the sex cells of a parent can cause a new trait to appear in the parent 's offspring. 
Sentence2: cancer of a parent's cells can cause a new trait to appear in their offspring.
[A]: appear


[Q]: Sentence1: a battery converts chemical energy into electrical energy. 
Sentence2: A battery produces a flow of electrons.
[A]: battery


[Q]: Sentence1: thick fur can be used for keeping warm. 
Sentence2: otters can be used to make clothing for keeping warm.
[A]:
for