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: Ejaculation allows males to reproduce. 
Sentence2: propelling sperm from the epididymes allows males to reproduce.

SOLUTION: allows

PROBLEM: Sentence1: Metabolic rate is the rate at which food is burned for energy. 
Sentence2: thyroid hormones increase the rate of energy consumption.

SOLUTION: energy

PROBLEM: Sentence1: the emission of sulfur dioxide causes acid rain. 
Sentence2: the emission of sulfur dioxide causes soil weathering.

SOLUTION:
causes