Front

What is the mid-ocean ridge?

Back

A mountain range on the ocean floor

Front

Sea-floor spreading happens when…

Back

New rock forms on the ocean floor

Front

Subduction

Back

When ocean crust sinks under another plate

Front

An ocean trench is...

Back

A deep valley under the ocean

Front

A hypothesis is...

Back

A testable idea based on facts

Front

How do fossils show that continents moved?

Back

The same fossils are found on different continents

Front

How does climate show that land has moved?

Back

Ice once covered places that are now warm

Front

How do land features help show how plates move?

Back

Some mountains on different continents fit together

Front

Why does the sea floor keep changing?

Back

Magma rises and makes new rock

Front

What happens to old ocean crust?

Back

It sinks into ocean trenches and melts