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: Most mammals have hair, or fur, covering their body. 
Sentence2: Most mammals have a body covering for keeping warm.
[A]: body


[Q]: Sentence1: Distance is measured in meters the SI unit of distance. 
Sentence2: The SI unit of distance is in meters.
[A]: SI


[Q]: Sentence1: building housing developments usually requires replacing animal habitats. 
Sentence2: building housing developments usually requires replacing animal burrows.
[A]:
animal