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: Methane gas is a produced by rotting compost, trash, and human waste. 
Sentence2: Methane gas can be produced by Slime molds.
Methane

Sentence1: People of all ages and activity levels perspire or sweat. 
Sentence2: Perspiration reduces body heat.
perspire

Sentence1: Skin color is a polygenic trait. 
Sentence2: Many polygenic traits are also influenced by environmental factors.

polygenic