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.

[EX Q]: Sentence1: harming an animal species has a negative impact on the population size of that species. 
Sentence2: Pesticides have a negative impact on the population size of a species.
[EX A]: impact

[EX Q]: Sentence1: electric devices require electrical energy to function. 
Sentence2: Lie detectors are electrical or mechanical devices.
[EX A]: devices

[EX Q]: Sentence1: Light passes through the camera lens and hits a mirror. 
Sentence2: Images are recorded by light passing through a lens and hitting a mirror.
[EX A]:
Light