A technique that uses sound waves to measure the depth of the ocean floor is

• dredging.
• sonar.
• SCUBA.
• weighted lines

Which of the following is an example of a connection between an ocean food web and a land food web?

• A polar bear eats a seal
• A whale eats a cod.
• A small fish eats plankton.
• A cod eats a small fish

A deep canyon in the ocean floor is called a(n)

• abyssal plain.
• seamount.
• trench.
• continental shelf.

Sea-floor spreading occurs in places where two plates are

• converging.
• diverging.
• motionless.
• breaking the surface.

Benthos are organisms that live

• on the surface of water.
• throughout the water column.
• on the ocean floor.
• in shallow water.

Which of the following organisms is an example of nekton?

• lobster
• dolphin
• clam
• sea star

Many organisms that live in the rocky intertidal zone are adapted to cling to the rocks to withstand the

• pounding of the waves.
• changes in salinity.
• periods of being underwater and exposed to air.
• changes in density.

A coastal inlet or bay in which freshwater from rivers mixes with salty ocean water is called a(n)

• transition zone.
• abyssal plain.
• estuary.
• hydrothermal vent.

Coastal wetlands that feature short, gnarled trees with arching prop roots are called

• mangrove forests.
• kelp forests.
• salt marshes.
• tide pools.

The part of the ocean that extends from the low-tide line to the edge of the continental shelf is the

• neritic zone.
• open-ocean zone.
• intertidal zone.
• deep zone.