Answer:
Water
Step-by-step explanation:
The substance that has a melting point at 0 and a boiling point at 100 is water. Water is the only substance that fits into this category. According to van.physics.illinois.edu, it states the following "For pure water, the boiling point is 100 degrees Celsius (212 Fahrenheit) at one atmosphere of pressure, and the melting point is 0 degrees Celsius (32 degrees Fahrenheit) at one atmosphere of pressure."
Answer: Water