What are fossils?

• Traces of living things preserved in Earth's crust

• Living creatures found in the ocean

• Rocks formed by volcanic activity

• Plants that have turned into stone

What is an example of an extinct creature mentioned in the passage?

• Giant dragonflies

• Dinosaurs

• Woolly mammoths

• Saber-toothed tigers

What do index fossils help scientists determine?

• The age of a rock layer

• The type of rock

• The location of ancient seas

• The size of ancient creatures

What is necessary for a fossil to form?

• The creature must be buried quickly

• The creature must be large

• The creature must be extinct

• The creature must be in a desert

What can cause rock layers to break and shift?

• Earthquakes

• Floods

• Wind

• Rain

What type of rock is formed from sand over millions of years?

• Sandstone

• Limestone

• Granite

• Marble

What happens to the soft parts of a creature's body when it becomes a fossil?

• They disappear

• They turn into stone

• They become hard

• They remain intact