Nitrogen cycle

What converts nitrogen gas into a usable form for plants and animals?

• bacteria

• rain

• fungi

• car exhaust

How is nitrogen "fixed" into a usable form for plants?

• Through action of bacteria only

• Through lightning only

• Through action of bacteria and lightning

• Through photosynthesis

How do animals get the nitrogen they need?

• From the air they breathe

• From the water they drink

• From the food they eat

• From the sun

What process occurs when dead plant and animal matter decomposes and nitrogen is released back into the atmosphere?

• Assimilation

• Fixation

• Ammonification

• Denitrification

_____ is the conversion of organic nitrogen into ammonia

• Nitrogen Fixation
• Ammonification
• Denitrification
• Assimilation 

Denitrification...

• animals eat the plants and other animals that contain nitrogen and release it through their waste

• Bacteria in the soil and lightning in the atmosphere “fix” the nitrogen

• nitrogen is released back into the atmosphere from the animal’s waste or decomposers

• plants absorb nitrogen through their roots and return it back to the atmosphere

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

• nitrogen fixation

• nitrification

• denitrification

• ammonification

• assimilation

What is true about nutrients in the ecosystem (such as water, carbon, and nitrogen)?

• They are not affected by humans in the ecosystem.

• They cannot be recovered if they are lost in the ecosystem.

• They cycle through the ecosystem in different forms to support life.

• They are usually only found in one form in the ecosystem to support life.

According to this diagram, plants use nitrogen to make _________________________

• carbohydrates

• cellulose

• proteins

• unsaturated fats

What happens to carbon during the process of photosynthesis?

• CO₂ is released by plants

• CO₂ is taken up by plants

• organic carbon is taken up through plant roots

• carbon is lost through heat