Question

Q29- Complete the following cycle given as by filling the blanks (a), (b), (c)
(d)​

Answer 1

Answer:

a) Lighting fixes nitrogen.

b) Nitrogen fixing bacteria &blue green algae fix atmospheric nitrogen.

c)Nitrogenous waste from excretion and death.

d) bacteria turn compounds of nitrogen into gaseous nitrogen

Answer 2

The answers to the given blanks are-

(a) Nitrogen fixation by lightning.

(b) Nitrogen fixation by nitrogen-fixing bacteria.

(c) The excretion and the death of animals releases nitrogen compounds into the soil.

(d) Denitrifying bacteria convert the compounds of nitrogen into atmospheric nitrogen.

What is nitrogen fixation?

• Nitrogen fixation is the fixing of atmospheric nitrogen into its compounds such as nitrites and nitrates.
• As plants cannot use atmospheric nitrogen directly, hence, nitrogen fixation is an essential process for the survival of living organisms.
• The nitrogen fixing bacteria and blue-green algae that are present in the soil are involved in nitrogen fixation and convert nitrogen into nitrites and then nitrates.
• Lightning also helps in nitrogen fixation and converts nitrogen into nitrogenous compounds.
• When plants or animals die, the nitrogen compounds are released into the soil where certain denitrifying bacteria convert it back to atmospheric nitrogen and thus, this cycle continues. This is called denitrification.