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: Ozone depletion results in higher levels of UV radiation reaching Earth. 
Sentence2: less ozone means more ultraviolet light.

SOLUTION: Ozone

PROBLEM: Sentence1: Leeches are external parasites. 
Sentence2: Leeches live on the surface of their hosts.

SOLUTION: Leeches

PROBLEM: Sentence1: Autotrophs are also called producers. 
Sentence2: autotrophs start food chains.

SOLUTION:
Autotrophs