Nitrogen Cycle Quiz

What percentage of the air does nitrogen constitute?

• 90%

• 30%

• 50%

• 78%

What is the process called when atmospheric nitrogen is converted to nitrogenous compounds?

• Nitrogenation

• Nitrogen fixation

• Nitrogen conversion

• Nitrogen transformation

What do nitrifying bacteria convert ammonia to?

• Nitrogen gas

• Ammonium nitrate

• Nitrites and nitrates

• Proteins

Apart from leguminous plants, how else can nitrogen fixation occur?

• Photosynthesis

• Respiration

• Lightning strikes

• Transpiration

What do plants use nitrates for?

• Making proteins

• Making vitamins

• Making lipids

• Making carbohydrates

What is the main source of nitrogenous wastes for the nitrogen cycle?

• Rainwater

• Volcanic ash

• Ocean water

• Dead plants and animal excreta

What is the role of denitrifying bacteria in the nitrogen cycle?

• Convert nitrogen gas to nitrates

• Convert nitrates back to atmospheric nitrogen

• Convert nitrates to ammonia

• Convert ammonia to nitrates

Water vapor leaves a plant in the biosphere and goes into the atmosphere through

• transpiration

• respiration

• precipitation

• evaporation

biosphere

• all the water on Earth

• regions that contain all the living things on Earth

• the envelope of gases that surrounds Earth

• living things on land

_____ moves underground to the ocean

• sea water

• groundwater

• lake water

• rain drops