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: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.

SOLUTION: bacteria

PROBLEM: Sentence1: hunting requires seeing prey. 
Sentence2: hunting requires seeing an animal.

SOLUTION: hunting

PROBLEM: Sentence1: Immunology is the study of the immune system. 
Sentence2: Immunology includes the study of antigens.

SOLUTION:
Immunology