14.4

Question 1

How do oil and natural gas form?

Answer 1

They form from the remains of dead marine organisms that sink and are buried by sediments. Heat and pressure transform it into oil and natural gas.

Question 2

What are oil rigs used for?

Answer 2

Oil rigs drill rocks on the ocean floor.

Question 3

What are gas hydrates?

Answer 3

Compact chemical structures made of water and natural gas, formed when bacteria break down organic matter trapped in ocean-floor sediments, producing methane gas.

Question 4

How do evaporative salts form?

Answer 4

As seawater evaporates, salt concentration increases until it is no longer dissolved, leading to the precipitation of salt deposits.

Question 5

What is desalination?

Answer 5

The process of extracting fresh water from ocean water.

Question 6

How is sand and gravel collected?

Answer 6

Suction devices are used to collect sand and gravel for use as landfill, to fill beaches, and in concrete.

Question 7

What are placer deposits?

Answer 7

Deposits formed from rivers carrying sediments into the ocean, where the flow slows and drops sediments along coastal areas.

Question 8

What are manganese nodules?

Answer 8

Hard lumps of manganese and iron, formed when metals precipitate around an object as molten substances and hot water are forced up through cracks along ridges, releasing minerals into seawater.