Biogeochemical Cycles & Biomolecules

Which compound does NOT contain carbon atoms?

• carbon dioxide

• ammonium

• calcium carbonate

• methane

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

• Water
• Atmosphere
• Sun
• Air

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

• respiration and photosynthesis
•  decomposition and respiration

How does the carbon in grass become part of a lion?

• The lion eats the grass
• Carbon from grass doesn't end up in a lion. 
• The carbon ends up in the lion's food chain. 
• The lion breathes in carbon given out by the plant

Organisms that do not decompose can be buried and become what?

• water
• nutrients
• air
• fossil fuels

The process of burning is called _____.

• decomposition
• combustion
• respiration

Which process takes carbon dioxide out of the atmosphere?

• respiration
• combustion
• decomposition
• photosynthesis

Burning fossil fuel has which effect in the carbon cycle?

• It removes carbon dioxide from the atmosphere.
• It puts carbon dioxide under the ground.
• It adds carbon dioxide to the atmosphere.
• It has no effect in the carbon cycle.

What is the an important element for living things.

• Neon
• Hydrogen
• Helium
• Carbon

Which nitrogen cycle process is occurring when plant roots absorb ammonium ions and nitrate ions for use in making molecules such as DNA, amino acids, and proteins?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation