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Science

Earth is the only planet we know of that supports life — but what exactly makes it tick? Dig into Earth's shape, structure, size, and surface as you begin your journey through space.

30 XP

Reward

10

Questions

5–10 min

Time

Q1 Question 1 of 10

What is the true shape of the Earth?

A perfect sphere An oblate spheroid — a sphere slightly flattened at the poles A flat disc An oval, like an egg

Q2 Question 2 of 10

Which layer of Earth do we live on?

The mantle The outer core The crust The inner core

Q3 Question 3 of 10

What is Earth's inner core made of?

Liquid iron and nickel Solid rock and stone Solid iron and nickel Gold and silver

Q4 Question 4 of 10

Which layer of Earth is liquid?

The crust The mantle The inner core The outer core

Q5 Question 5 of 10

Approximately how much of Earth's surface is covered by water?

About 30% About 50% About 71% About 90%

Q6 Question 6 of 10

How old is planet Earth?

About 6,000 years About 65 million years About 4.5 billion years About 13.8 billion years

Q7 Question 7 of 10

How many continents does Earth have?

5 6 7 8

Q8 Question 8 of 10

Which layer of Earth is the thickest?

The crust The mantle The outer core The inner core

Q9 Question 9 of 10

Earth is the __ planet from the Sun.

First Second Third Fourth

Q10 Question 10 of 10

What is Earth's diameter (distance straight through the center)?

About 1,275 km About 12,756 km About 127,560 km About 1,392,000 km

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