About the video _ EARTH 101

How old is Earth?

• 3 billion years
• 4.5 billion years
• 5 billion years
• 6.5 billion years

What caused Earth to form?

• Explosions in space
• Particles coming together
• The Sun breaking apart
• Earth's atmosphere forming

What is at the center of Earth?

• A solid inner core
• A liquid outer core
• A rocky crust
• A layer of silicate rocks

What is Earth's position in the solar system?

• First planet from the Sun
• Second planet from the Sun
• Third planet from the Sun
• Fourth planet from the Sun

Why does Earth have liquid water?

• It is far away from the Sun.
• It is close enough to the Sun to stay warm, but not too close.
• Its surface traps the heat.
• It has a strong atmosphere.

What is one theory about Earth's water?

• It came from meteors.
• It is younger than the rocks.
• It is as old as Earth's rocks.
• It formed in space.

How does water affect Earth’s surface?

• It only helps create oceans.
• It forms nutrient-rich soil, oceans, and adds moisture to the atmosphere.
• It evaporates quickly.
• It stays frozen most of the time.

When did primitive life appear on Earth?

• 4.5 billion years ago
• 3.8 billion years ago
• 2.5 billion years ago
• 1 billion years ago

How many species have been catalogued on Earth?

• 500
• 1 million
• 1.5 million
• 2.5 million

Why is Earth's biodiversity unique?

• It includes plants, animals, bacteria, fungi, and more.
• It only has animals and plants.
• It is smaller than other planets' biodiversity.
• It is less diverse than scientists expected.