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.

Sentence1: Lions live in social groups called prides. 
Sentence2: Chimpanzees live in social groups called communities.
groups

Sentence1: Bound and free ribosomes are structurally identical and interchangeable. 
Sentence2: Bound and free structures are in the cytoplasm where proteins are made.
Bound

Sentence1: an incandescent light bulb converts electricity into light by sending electricity through a filament. 
Sentence2: a light bulb converts energy into light by sending energy through a filament.

bulb

