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: condensing causes a liquid to form. 
Sentence2: Air carries moisture that causes a liquid to form.

SOLUTION: causes

PROBLEM: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: Common fossils include plant fossils like ferns.

SOLUTION: plant

PROBLEM: Sentence1: when electricity flows to a light bulb , the light bulb will turn on. 
Sentence2: when energy flows to a light bulb, it will turn on.

SOLUTION:
bulb