Earth's Cycles

When humans burn fossil fuels, most of the carbon quickly enters the                       as carbon dioxide.

• Water
• Atmosphere
• Sun
• Air

Which one of these does not add CO2 to the atmosphere?

• cooking with gas
• planting trees
• burning wood
• riding in a bus

What does not produce carbon dioxide?

• Photosynthesis
• Burning Fossil Fuels
• Animal respiration
• Plants decaying

How do living organisms return carbon to the atmosphere in the carbon cycle?

• respiration and photosynthesis
•  decomposition and respiration

What is the energy source for the water cycle?

• the sun
• the earth
• water
• the moon

What is evaporation?

• The part of the water cycle when the sun heats up water, turning it from a liquid into water vapor or steam. It rises from the ground into the air.
• The part of the water cycle when the water vapor in the air gets cold. The water turns back into a liquid and forms clouds.
• The part of the water cycle when clouds get heavy and can no longer hold the liquid water. This causes the water to fall from the sky to the earth as rain, snow, sleet, or hail.

Tags

NGSS.MS-ESS2-4

What is condensation?

• The part of the water cycle when the sun heats up water, turning it from a liquid into water vapor or steam. It rises from the ground into the air.
• The part of the water cycle when the water vapor in the air gets cold. The water turns back into a liquid and forms clouds.
• The part of the water cycle when clouds get heavy and can no longer hold the liquid water. This causes the water to fall from the sky to the earth as rain, snow, sleet, or hail.

Tags

NGSS.MS-ESS2-4

How much of the atmosphere is composed of nitrogen gas?

• 87%
• 38%
• 78%
• 21%

How do plants get the nitrogen they need?

• from the air
• from the soil or water in which they live
• from the Sun
• from broken-down rocks

Why do all organisms need nitrogen?

• To live and grow 
• To build phosphorus
• To make oxygen levels grow
• To help blood circulate better