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: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Life without protein is impossible.

SOLUTION: proteins

PROBLEM: Sentence1: Blood is a fluid connective tissue. 
Sentence2: A fluid connective tissue carries oxygen to the brain.

SOLUTION: connective

PROBLEM: Sentence1: Diurnal cycles Diurnal cycles are the daily cycles of light and darkness. 
Sentence2: Plants detect and respond to diurnal cycles.

SOLUTION:
Diurnal