Seafloor spreading

The youngest rocks on the ocean floor are located ____.

• near continents

• at mid-ocean ridges

• far from mid-ocean ridges

• near Asia

The crust and upper mantle make up Earth's ____.

• asthenosphere

• lithosphere

• core

• continents

The scientist credited with sea-floor spreading is _________

• Alfred Wegener, a German scientist

• Harry Hess, an American geologist

• J.Tuzo Wilson, a Canadian scientist

• Kenn Bulaso, a Filipino educator

The process of ___________ continually adds new crust to the ocean floor along both sides of the mid-ocean ridge.

• plate tectonics

• seafloor spreading

• continental drift

• convection

What is formed at the subduction zone?

• mountain ranges

• deep-sea trenches

• oceanic ridge

• hills and valleys

What particular event is shown on the picture?

• mid-ocean ridge

• subduction zone

• transform boundary

• divergent boundary

In sea-floor spreading, molten material rises from the mantle and erupts

• in deep-ocean trenches

• along the edges of all the continents

• along mid-ocean ridges

• at the north and south plate

The ocean floor sinks beneath a deep-ocean trench and back into the mantle in a process known as ________.

• convection

• subduction

• continental drift

• plate tectonics

What technology did scientists use in the mid-1900s to map the mid-ocean ridge?

• satellites

• submarines

• deep-sea diving

• sonar

A vast, underwater mountain chain is called a(n) _________.

• ocean ridge

• oceanic crust

• deep-sea trench

• ocean floor sediment