Water Cycle
What process changes liquid water into water vapor?
Evaporation
Which process takes in carbon dioxide and releases oxygen?
Photosynthesis
What type of tiny organisms in the soil change nitrogen into a form plants can use?
Bacteria
Where is most phosphorus stored on Earth?
Rocks and soil
When water vapor cools and forms clouds, this process is called:
Condensation
What human activity releases extra carbon dioxide into the atmosphere?
Burning fossil fuels
Why do plants and animals need nitrogen?
To build proteins and DNA
Unlike other cycles, the phosphorus cycle does NOT have which phase?
Gas
Water falling to Earth as rain, snow, or sleet is called:
Precipitation
What is the main way carbon is returned to the atmosphere?
Respiration
What happens when too much nitrogen from fertilizers enters rivers and lakes?
Algal blooms
How do plants get phosphorus?
By absorbing it from the soil
Water that moves across land and flows into rivers or lakes is called:
Runoff
Carbon is stored in all living things because it is found in:
DNA, proteins, and food
Which of the following is NOT part of the nitrogen cycle?
Photosynthesis
What human activity adds too much phosphorus into water systems?
Fertilizer runoff
What human activity pollutes the water cycle the most?
Throwing trash in rivers
Which human activity removes trees that absorb carbon dioxide?
Deforestation
What gas makes up most of the air but must be changed by bacteria before plants can use it?
Nitrogen
Why is phosphorus important for living things?
It helps make DNA and bones