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.

[Q]: Sentence1: Carbon cycles quickly between organisms and the atmosphere. 
Sentence2: the atmosphere is essential to all living organisms.
[A]: organisms


[Q]: Sentence1: Angiosperm sporophyte is dominant. 
Sentence2: Flowers form on angiosperms.
[A]: Angiosperm


[Q]: Sentence1: Mammals are a class of animal. 
Sentence2: When a mammal's habitat is destructed, it causes the mammal to move to find shelter in another habitat.
[A]:
Mammals