Sea-Floor Spreading Check-up

Sea-floor spreading begins at the 

• Deep ocean trench
• Mid-ocean ridge
  Mid-ocean ridge
• Continent's edge

Magma, or molten material, __________ and hardens once it reaches the surface of the ridge.

• cools
• warms
• shrinks

The oceanic crust is pushed aside on both sides of the 

• Continent's edge
• Deep-ocean trench
• Mid-ocean ridge

The oceanic crust _________ when it reaches the continental crust.

• sinks
• rises
• expands

The process that happens at the deep-ocean trench is called...

• sea-floor spreading
• adding material to the ocean floor
• subduction

The land feature that happens when there is subduction is called a...

• mid-ocean ridge
• deep-ocean trench
• asthenosphere

New crust is always formed at the...

• mid-ocean ridge
• deep-ocean trench
• asthenosphere

Older crust is found towards the...

• Mid-ocean ridge
• Deep-ocean trench
• Asthenosphere

If there are MORE mid-ocean ridges than subduction zones, what happens to the ocean?

• It gets larger
• It gets smaller
• It sinks

If there are more subduction zones than mid-ocean ridges, what happens to the ocean?

• It gets bigger
• It gets smaller
• It sinks and rises