2nd 6 Weeks Review

Which nitrogen cycle process is occurring when bacteria convert ammonium to nitrite and then into nitrate?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

Which of these nitrogen cycle processes converts atmospheric nitrogen to a soil form of nitrogen that is usable by plants?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

How much of the atmosphere is composed of nitrogen gas?

• 87%
• 38%
• 78%
• 21%

Organisms that break down dead plants & animals and release nitrogen back into atmosphere...

• bacteria
• plants
• animals
• producers

Organisms that need nitrogen to survive

• only plants
• only animals
• only bacteria
• all living organisms

Plants and animals cannot use nitrogen directly from the air.

• True
• False

After plants and animals contain nitrogen, what puts it back into atmosphere and soil?

• decomposition
• precipitation
• condensation
• bacteria

Nitrification happens in the ______

• Air 
• Soil 
• Ground Water 
• Plants 

How does a farmer's fertilizer cause a dead zone in the ocean?

• What is used on land has no interaction with what happens in the ocean.

• The run off from the farm brings nitrogen to the ocean. This increases the population size of all organisms. The presence of so many organisms, like fish, in a single area causes sharks and other predators to come. When they consume all the organisms in the area, it becomes known as a dead zone.

• The run off from the farm brings nitrogen to the ocean. This causes the algae population to grow quickly. When they die the decomposers break them down and use up all the oxygen in the water. If there is no oxygen, nothing can live.

Water run off from a farm can result in cause algae in the ocean to grow out of control.

• TRUE

• FALSE