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

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

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

Which of these correctly shows the reservoirs where most of Earth's carbon atoms and nitrogen atoms are residing at any given time?

• 
• 
• 
• 
• 

Tags

NGSS.HS-ESS2-6

Which nitrogen cycle process is occurring when nitrogen in plant or animal protein is converted to ammonium?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

Tags

NGSS.MS-LS2-3

Which of these nitrogen molecules would be present in the atmosphere?

• NH₃

• NH₄⁺

• NO₃^-

• N₂

Tags

NGSS.MS-ESS2-1

NGSS.MS-LS2-3

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

When deciduous trees shed their leaves, specialized soil bacterial will consume the leaf material for energy and, in the process, will return some of the leaf nitrogen to the soil. What nitrogen cycle process is taking place?

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

Tags

NGSS.MS-LS2-3

According to this diagram, plants use nitrogen to make _________________________

• carbohydrates

• cellulose

• proteins

• unsaturated fats

What is the process of combining nitrogen gas with other elements to make nitrogen into usable compounds?

• nitrogen composition
• ammonia 
• nitrogen fixation
• denitrification

How much of the atmosphere is composed of nitrogen gas?

• 87%
• 38%
• 78%
• 21%