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: Specialization decreases mortality 12,13 and increases survival. 
Sentence2: evolving different adaptations increases survival.
answer:
increases


question:
Sentence1: when a gas in an open container evaporates , that gas spreads out into the air. 
Sentence2: when a gas in an open container evaporates gas molecules slamming into one another.
answer:
container


question:
Sentence1: optical tools are used for observing materials up close. 
Sentence2: Optical tools are used for observing things that are smaller than they appear.
answer:

observing