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: Battery electricity comes conversion.
[A]: battery


[Q]: Sentence1: If there is a fierce emotion near a stream, that stream somehow records that. 
Sentence2: when runoff or water seeping out of a spring when there is fierce emotion it can record it.
[A]:
emotion