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.

Sentence1: Algae have varied life cycles. 
Sentence2: And fish eat algae.
Algae

Sentence1: Soil Erosion Soil erosion is a natural process. 
Sentence2: wind and rain is a natural process.
natural

Sentence1: moss causes chemical weathering. 
Sentence2: Moss can cause a chemical breakdown of rocks.

moss