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 circle graph can be used to display percents. 
Sentence2: pie charts are circle graphs.

A: circle
****
Q: Sentence1: Fe is the periodic symbol for Iron. 
Sentence2: Chemical weathering causes FE in rock to oxidize.

A:
Fe
****