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: Humans have collected and grown mushrooms for food for thousands of years. 
Sentence2: Yeast and mushrooms are types of fungus.

A: mushrooms
****
Q: Sentence1: Earth's Atmosphere Earth's atmosphere is the layer of gasses that surrounds the earth. 
Sentence2: weather refers to the conditions in the layer of gasses that surrounds the earth.

A: earth
****
Q: Sentence1: Chromoplasts make and store pigments. 
Sentence2: chromoplasts make and store permanent colors.

A:
Chromoplasts
****