Ch 9 Review

The presence of the same ____ on several continents supports the hypothesis of continental drift.

• fossils
• rocks
• neither a nor b
• both a and b

The hypothesis that continents have slowly moved to their current locations is called ____.

• continental drift
• continental slope
• magnetic reversal
• convection

A lack of explanation for continental drift prevented many scientists from accepting that a single supercontinent called ____ once existed.

• Glomar
• Glossopteris
• Pangaea
• Wegener

Continental drift states that continents have moved ____ to their current location.

• vertically
• slowly
• quickly
• very little

Continental drift was not widely accepted when it was first proposed because ____.

• Wegener couldn’t explain why or how the continents moved
• continental landmasses were too big to move slowly over Earth’s surface
• magnetic and sonar data proved that Wegener’s hypothesis was incorrect
• mantle convection currents weren’t in motion at that time

How does the size of the pacific ocean compare now to 50 million years ago.

• The Pacific ocean is larger today
• The Pacific ocean is smaller today
• The size of the Pacific ocean hasn't changed over the last 50 million years

The youngest rocks on the ocean floor are located ____.

• near continents
• at mid-ocean ridges
• far from mid-ocean ridges
• near Asia

The alignment of iron minerals in rocks when they are formed reflects the fact that Earth's ____ has reversed itself several times in the past.

• magnetic field
• core
• asthenosphere
• gravity

Seafloor spreading occurs because ____.

• new material is being added to the asthenosphere
• earthquakes break apart the ocean floor
• sediments accumulate at the area of spreading
• molten material beneath Earth's crust rises to the surface

While studying the ocean floor, scientists found ____ bands of magnetism.

• plastic
• alternating
• no
• rectangular