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: forming coal requires decaying vegetation. 
Sentence2: Forming fossil fuels requires decaying vegetation.
decaying

Sentence1: Mammalian predators include the coyote and bobcat. 
Sentence2: a coyote's teeth is important for digestion.
coyote

Sentence1: Antigens are found on cancer cells and the cells of transplanted organs. 
Sentence2: transplanted organs can trigger an immune response.

organs