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: Infection is what ultimately leads to death. 
Sentence2: scraping oneself on a contaminated object may cause death.

SOLUTION: death

PROBLEM: Sentence1: Viruses are parasites of cells. 
Sentence2: Populations of viruses do not grow through division because they are parasites.

SOLUTION: are

PROBLEM: Sentence1: Bivalves feed on plankton and nonliving organic matter. 
Sentence2: Scallops, oysters and clams are bivalves.

SOLUTION:
Bivalves