Earth's Systems: Water and Weather — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. About what percent of Earth's water is found in oceans as salt water?
A) 97 percent
B) 50 percent
C) 25 percent
D) 3 percent
Roughly 97 percent of water is in oceans, leaving only 3 percent as freshwater on the planet.
2. Where is the largest share of Earth's freshwater stored?
A) Rivers and streams
B) Glaciers and polar ice
C) Underground aquifers
D) Clouds in the atmosphere
Glaciers and ice caps hold most of Earth's freshwater, frozen and largely inaccessible to people.
3. Which interaction best describes a hurricane gaining strength over warm ocean water?
A) Geosphere with biosphere
B) Atmosphere with biosphere
C) Atmosphere with hydrosphere
D) Geosphere with atmosphere
Warm seawater evaporates and feeds energy and moisture into the storm's atmospheric circulation.
4. Which statement best distinguishes climate from weather?
A) Climate is forecast hourly; weather is predicted yearly.
B) Climate is short-term; weather is long-term.
C) Climate only happens at sea; weather only on land.
D) Climate is long-term average; weather is short-term conditions.
Scientists use long-term averages of weather over many years to define a region's climate.
Part B: Fill in the Blank
Write the correct answer on each line.
1. If global temperatures rise, glaciers melt and add freshwater to the oceans.
Melting ice raises sea level and shifts the balance between salt water and freshwater storage.
2. A long period of below-average rainfall in a region is called a drought.
Droughts stress plants, animals, and water supplies and often relate to long-term climate patterns.
3. Warmer ocean water can fuel stronger storms, an example of energy moving from the hydrosphere to the atmosphere.
Heat energy from the ocean transfers to the air, increasing storm strength and rainfall potential.
4. Cutting down a forest reduces transpiration and changes how much water enters the atmosphere.
Transpiration moves water from soil through plants into the air, influencing local weather.
5. Only about 1 percent of Earth's water is liquid freshwater that humans can easily use.
Most freshwater is frozen, leaving roughly one percent in lakes, rivers, and shallow groundwater.