Question

20The image explains a nitrogen cycle.What should be added to the blank box to complete the cycle? *
1 point

(a) Bacteria turn fixed nitrogen into nitrogenous compounds.
(b) Bacteria fixed nitrogen into soil.
(c) Bacteria convert the nitrogenous compounds into nitrogen gas.
(d) Bacteria mix nitrogen gas with the soil.​

Answer 1

Answer:

a) Nitrogen-fixing bacteria are prokaryotic microorganisms that are capable of transforming nitrogen gas from the atmosphere into “fixed nitrogen” compounds, such as ammonia, that are usable by plants.

b) Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria such as Azotobacter and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.

c) Nitrogen-fixing bacteria in the soil and within the root nodules of some plants convert nitrogen gas in the atmosphere to ammonia. Nitrifying bacteria convert ammonia to nitrites or nitrates. Ammonia, nitrites, and nitrates are all fixed nitrogen and can be absorbed by plants.

d) These bacteria have the nitrogenase enzyme that combines gaseous nitrogen with hydrogen to produce ammonia. ... Nitrificaton: Nitrification is the conversion of ammonia (NH3) to nitrate (NO3–). It is usually performed by soil living bacteria, such as nitrobacter.

Answer 2

The answer of this question is ( b )