Salt Water vs Fresh Water

Question 1

Which human activity most directly reduces the amount of fresh water stored in lakes and rivers?

Accepted Answer

Diverting water from rivers for irrigation

Answer

Building houses on a beach

Answer

Planting trees in a forest

Answer

Recycling plastic bottles

Question 2

Scientists report that 97.5 % of Earth’s water is salt water in the oceans and 2.5 % is fresh water. Of the fresh water, 68.7 % is locked in ice, 30.1 % is groundwater, and 1.2 % is surface water in lakes and rivers. Humans can only use the groundwater and surface water. If humans currently use 70 % of the water that is accessible to them, what percent of all the water on Earth is being used by humans? Express your answer as a percent rounded to the nearest hundredth.

Accepted Answer

0.55 %

Answer

2.5 %

Answer

0.78 %

Answer

1.75 %

Question 3

A scientist shows a graph of Earth’s water distribution. The graph shows that 97% of the Earth’s water is salt water in the oceans, 2% is freshwater locked in glaciers and ice caps, and 1% is freshwater in lakes, rivers, and underground. Humans use about 70% of the freshwater in lakes and rivers for drinking, farming, and industry. Which statement best describes the impact of human use on the Earth’s freshwater resources?

Accepted Answer

Human activities consume most of the readily available freshwater, leaving only a small fraction of the total Earth’s water for ecosystems and future use.

Answer

Because the oceans contain 97% of water, using freshwater does not change the total amount of water on Earth.

Answer

Most of the Earth’s freshwater is stored in glaciers, so human use of lakes and rivers does not affect the overall water supply.

Answer

Human use has little effect because only 1% of Earth’s water is freshwater, so any consumption is negligible.

Try three questions

Which human activity most directly reduces the amount of fresh water stored in lakes and rivers?

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