instruction:
Given a scientific question, generate a correct answer to it.
question:
What done ozone help protect against?
answer:
ultraviolet rays

question:
Who created the idea of an evolutionary tree to represent the relationships between different species and their common ancestors?
answer:
charles darwin

question:
Earth is the only planet in the solar system that has what element, which is essential for human life, present in all three of its states?
answer:
water