instruction:
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.
question:
Sentence1: Protozoa make humans sick when they become human parasites. 
Sentence2: paramecium are single celled animals that make humans sick when they become human parasites.
answer:
become


question:
Sentence1: a light bulb is used for seeing in the dark. 
Sentence2: Conventional light bulbs generate light by heating a filament.
answer:
bulb


question:
Sentence1: Some species of reptiles can go several weeks between meals. 
Sentence2: Reptiles lay eggs protected by leathery shells.
answer:

reptiles