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: Chemical weathering is the chemical disintigration of rocks. 
Sentence2: moss causes the chemical disintigration of rocks.
[A]: chemical


[Q]: Sentence1: Mad Cow disease is a concern. 
Sentence2: pathogens can cause Mad Cow.
[A]: Cow


[Q]: Sentence1: Habitat loss and hunting are the two major causes for their declining populations. 
Sentence2: Habitat loss and hunting can cause harm to an animal species.
[A]:
Habitat