TASK DEFINITION: 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.
PROBLEM: Sentence1: hearing is used for sensing sound by animals. 
Sentence2: functioning ears are used for sensing sound by animals.

SOLUTION: animals

PROBLEM: 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.

SOLUTION: appear

PROBLEM: Sentence1: Like the retina of the eye, the intense light of the Sun can burn the imager damaging the camcorder. 
Sentence2: Looking at bright objects have a negative impact on the retina.

SOLUTION:
retina