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: looking at bright objects has a negative impact on the eyes. 
Sentence2: Looking at bright objects have a negative impact on the retina.

A: bright
****
Q: Sentence1: Among families with children the average number of offspring is 1.8. 
Sentence2: information in an organism's chromosomes cause genetic traits to be passed down to that organism's children.

A: children
****
Q: Sentence1: Echinoderms lack a centralized nervous system. 
Sentence2: Starfish and sea urchins are also echinoderms.

A:
Echinoderms
****