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: Ovulation is the release of an egg from an ovary. 
Sentence2: The release of an egg during ovulation is used in reproduction.

SOLUTION: Ovulation

PROBLEM: Sentence1: protein is used to repair cells by the human body. 
Sentence2: Wound healing requires protein.

SOLUTION: protein

PROBLEM: Sentence1: Healing requires energy. 
Sentence2: energy requires rest.

SOLUTION:
energy