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: a light bulb is used for seeing in the dark. 
Sentence2: Conventional light bulbs generate light by heating a filament.

SOLUTION: bulb

PROBLEM: Sentence1: Every photograph is produced by a camera. 
Sentence2: Photographers record images.

SOLUTION: photograph

PROBLEM: Sentence1: Fertilization occurs when a sperm and an egg fuse to form a diploid zygote. 
Sentence2: A baby girl will be the result of female sperm fusing with an egg to form a diploid zygote.

SOLUTION:
diploid