question: Write a question you would see in a school textbook.
answer: Which of these explains how a trench can form?

question: Write a question you would see in a school textbook.
answer: What is significant about the discovery of water on Mars?

question: Write a question you would see in a school textbook.
answer:
Some of Earth's water is stored underground in porous rock formations known as aquifers. Which of these could use up groundwater in aquifers?