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: Lymph is a fluid that leaks out of capillaries into spaces between cells. 
Sentence2: Humans are made up of trillions of cells.

A: cells
****
Q: Sentence1: Mangoes are propagated vegetatively and by seeds. 
Sentence2: animals propagate mangoes.

A: Mangoes
****
Q: Sentence1: Hay fever is caused by an allergy to pollens or moulds. 
Sentence2: Hay fever is caused by plant reproduction.

A:
Hay
****