TASK DEFINITION: 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.
PROBLEM: Sentence1: Capillaries are microscopic vessels. 
Sentence2: Lymph is a fluid that leaks out of microscopic vessels into spaces between cells.

SOLUTION: microscopic

PROBLEM: Sentence1: Methane gas is a produced by rotting compost, trash, and human waste. 
Sentence2: Methane gas can be produced by Slime molds.

SOLUTION: Methane

PROBLEM: Sentence1: the fallopian tubes are used in reproduction. 
Sentence2: reproduction requires eggs to fertilize.

SOLUTION:
reproduction