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: Mammals depend on the vegetation for food and shelter. 
Sentence2: Mammals are Heterotrophs.

SOLUTION: Mammals

PROBLEM: Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: Chordates are vertebrates.

SOLUTION:
Chordates