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: Rainy clouds cause rain, and excess water vapor from clouds is the basis of rainbows. 
Sentence2: Condensation can lead to rain.
[A]: rain


[Q]: Sentence1: Algae have varied life cycles. 
Sentence2: And fish eat algae.
[A]: Algae


[Q]: Sentence1: if an object reflects light toward the eye then that object can be seen. 
Sentence2: Light is focussed on the retina.
[A]:
light