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: Scientists still know relatively little about Archaea. 
Sentence2: scientists still know relatively little about non-bacterial prokaryotes.

SOLUTION: Scientists

PROBLEM: Sentence1: All cells share some of the same structures and basic functions. 
Sentence2: Inside the cell is a structure called the nucleus.

SOLUTION: cells

PROBLEM: Sentence1: Bacteria are normally classified as either 'good' bacteria or 'bad' bacteria. 
Sentence2: Viruses can infect good and bad types.

SOLUTION:
'bad'