What is the structure of the Earth?

What are the relative sizes of each layer in the Earth's structure?

In which part of the Earth's structure are all minerals and other resources found?

What are tectonic plates?

Why do the tectonic plates move?

What was the Earth's early atmosphere like?

How was oxygen produced?

What are the main gases in the atmosphere?

How can gases be separated?

What is the carbon cycle?

Why has the amount of carbon dioxide in the air increased recently?