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: if an object is black then that object absorbs all visible light. 
Sentence2: Something is black if it absorbs visible light and doesn't reflect.
[A]: light


[Q]: Sentence1: If there is an increase in UV radiation, the risks go up for all types of skin cancer. 
Sentence2: Ozone depletion increases the risks for all types of skin cancer.
[A]: all


[Q]: Sentence1: the Himalayas were formed by rock folding. 
Sentence2: If the rocks are not as brittle, they will either tilt or fold.
[A]:
rock