Ecosystems and Cycles

The changing of liquid to a gas is

• condensation
• precipitation
• evaporation
• boiling water

The changing of a gas into a liquid as the gas cools. 

• runoff
• compost
• condensation
• evaporation

Precipitation is

• The water that sinks beneath the ground and collects in tiny holes in a soil and rock.
• The changing of a liquid to a gas.
• Rain, snow, sleet or hail.
• Lightning striking the ground. 

What is the carbon cycle?

• The continuous changing of nitrogen gas into compound is the soil and later released back into the air. 
• Precipitation that flows over the land's surface into rivers and lakes and is not absorbed into the ground. 
• The continuous exchange of carbon among living things. 
• The constant movement of water as a liquid and a gas between Earth's air and its surface. 

A mixture of decayed plant and animal material that ca be used as fertilizer. 

• runoff
• compost
• groundwater
• evaporation

What is the nitrogen cycle?

• The continuous changing of nitrogen gas into compounds in the soil and later released back into the air.
• Continuous exchange of carbon among living things. 
• The changing of a liquid into a gas.
• The change of gas into a liquid as the gas cools.

Runoff is 

• The water that sinks beneath the ground and collects in tiny holes in soil and rock. 
• A mixture of decayed plants and animal material. 
• Precipitation that flows over the land's surface into rivers and lakes and is not absorbed into the ground. 
• The precipitation that runs into a pool in your backyard. 

What is groundwater?

• The water that sinks beneath the ground and collects in tiny holes in soil and rock. 
• A mixture of decayed plants and animal material. 
• The precipitation that runs into a pool in your backyard. 
• Precipitation that flows over the land's surface into rivers and lakes and is not absorbed into the ground. 

"Plants can live without animals, but animals cannot live without plants." Is this statement true? 

• No, not all animals eat plants. Animals can eat other animals to get the nitrogen they need. 
• Yes, animals need plants for food, oxygen and nitrogen. Plants need animals, ike bees to help them reproduce.

What energy is needed for the changes in the water cycle to occur?

• wind
• nitrogen cycle
• electric
• sun