Plants are capable of using nitrogen directly from the atmosphere.

• True
• False

Only plants are capable of making protein directly from nitrates.

• True
• False

Nitrogen fixation is a process that changes nitrogen within plants and soil into ______

• Nitrates
• Nitrogen
• Oxygen
• Carbon Dioxide 

Plants use nitrates to form ____

• Protein
• Food
• Sugar
• Stems

Math the terms in its order:
1. Necessary organisms in the nitrogen cycle
2. Release of nitrogen from nitrogen compounds
3. Process of obtaining energy from food 
4. Forms as water vapor condenses 
5. Use plants for food

• 4,3,5,2,1
• 1,2,3,4,5
• 5,4,3,2,1
• 3,5,4,2,1

Carbon Dioxide is kept at a constant level by an exchange between the atmosphere and: 

• Rock
• Living Things 
• Space
• The Oceans 

The two basic processes of life involved in the carbon-oxygen cycle are:

• Fixation and Dentrification
• Respiration and Photosynthesis
• Condensation and Precipitaion
• Respiration and Fixation 

People return carbon stored in fossil fuels to the carbon-oxygen cycle by burning:

• Wood
• Coal and Oil
• Candles
• Vegetation

The process of changing a gas to a liquid is known as:

• Condensation
• Evaporation
• Precipitaion
• Sublimation

The process of changing a liquid to a gas is:

• Condensation 
• Evaporation
• Precipitation
• Sublimation