Nitrogen Cycle

Q.

Question 30
Choose the forms in which most plants absorb nitrogen

(i) Proteins
(ii) Nitrates and Nitrites
(iii) Urea
(iv) Atmospheric nitrogen

(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)

Q. Some plants cannot take the atmospheric nitrogen directly. They take in nitrogen in usable forms like:

1. Nitrates
2. Nitrites
3. Nitrogen dioxide
4. Nitric acid

Q.

Most of the plants absorb nitrogen in one of the following forms. This is :
(a) proteins (b) nitrates and nitrites (c) urea (d) atmospheric nitrogen

Q.

Name of bacterium responsible for fixing atmospheric nitrogen in groundnut plant? [1 MARK]

Q. The decomposers in an ecosystem ______.

1. convert inorganic materials to simpler forms.
2. convert organic materials to inorganic forms.
3. convert inorganic materials into organic compounds.
4. do not breakdown organic compounds.

Q.

Rhizobium bacterias are present in root nodules of leguminous plants.

1. True
2. False

Q.

Plants are called autotrophs because they:

1. Because they depend on other organisms for energy and all nourishment.

2. Because they capture energy from sunlight and give it to animals to make their food.

3. Because they derive their energy directly from the sun to produce food for themselves.

4. Because they generate energy and food on their own.

Q. Oxides of nitrogen and sulphur form when they react with water vapour present in atmosphere.

1. bases
2. salts
3. acids

Q. Which one of the following is detrimental to soil fertility?

1. Saprophytic bacteria
2. Nitrobacter
3. Pseudomonas
4. Nitrosomonas