Schoolnet Week #23

Most of the oxygen in Earth’s atmosphere is produced in the top six inches of the oceans. Which best explains this?

• Oxygen is produced by photosynthetic microorganisms that live near the surface of the ocean.

• Oxygen is produced by seawater, which evaporates into pure oxygen and hydrogen.

• Oxygen is produced as a by-product as fish breathe through their gills.

Which percentage represents the amount of Earth’s water that is found in oceans?

• 3%

• 71%

• 97%

A new town is established in a remote mountain area. The citizens of the new town are concerned about the health of themselves and their environment. Which aspect of the community should the town develop first to meet their concerns?

• clean water source

• fine restaurants

• good roads

How is the amount of oxygen in ocean water affected by temperature?

• cold water can hold more oxygen than warm water

• warm water can hold more oxygen than cold water

• the amount of oxygen in the water is not affected by the water temperature

Scientists notice that many fish are dying in a local lake. Which water quality data would they most likely gather to determine the cause of the fish kill?

• water depth

• dissolved oxygen

• speed of water flow

Which dissolved gas is added to ocean water as a result of photosynthesis?

• nitrogen

• carbon dioxide

• oxygen

Where is most of the freshwater on Earth?

• in glaciers and icecaps

• in groundwater

• in rivers and streams

Which is an unlikely source of water for a river?

• melting snow

• rainwater

• oceans

Which would best indicate that water taken from a local waterway was unsafe for drinking?

• dead fish in the water

• warm temperature

• cloudy water

How do oceanic upwellings promote the growth of plankton?

• They bring nutrients up to the surface of the ocean

• upwellings bring up cold water that promotes the growth of plankton

• They decrease the levels of oxygen at the surface of the ocean.