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: Amphibians have permeable skin that easily absorbs substances from the environment. 
Sentence2: permeable skin easily absorbs air to breathe through.
answer:
absorbs


question:
Sentence1: All rockets generate thrust by igniting an mixture of fuel and 'oxidiser'. 
Sentence2: Igniting a mixture of fuel and "oxidiser" causes a rocket to move.
answer:

'oxidiser'