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: Contact with infected blood, contaminated needles. 
Sentence2: scraping oneself on an infected needle may cause infection.

SOLUTION: infected

PROBLEM: Sentence1: Endospores are commonly found in soil and water. 
Sentence2: Some bacteria form resistant cells called endospores.

SOLUTION: Endospores

PROBLEM: Sentence1: Douglas Fir trees have fir cones. 
Sentence2: Conifers do not change colors with the season.

SOLUTION:
cones