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: Mollusks are invertebrates such as the common snail. 
Sentence2: snails have no backbone.
answer:
snail


question:
Sentence1: Specialization occurs when competing species evolve different adaptations. 
Sentence2: evolving different adaptations increases survival.
answer:
adaptations


question:
Sentence1: Rocks and grasses glisten with dew. 
Sentence2: rocks and grasses glisten when water vapor condenses over night.
answer:

Rocks