CBSE 2025 · Region 7 · Set 3 · Q20 · 2 marks
Ravi lives in a village where he suggested to the local farmers to introduce a fungus as biofertilizer into their crop fields. State the benefits provided by the fungus to the crop.(b)How do secondary lymphoid organs provide immunity?(ii)Highlight the role of spleen as an organ that provides immunity.
Ravi lives in a village where he suggested to the local farmers to introduce a fungus as biofertilizer into their crop fields. State the benefits provided by the fungus to the crop.
(b)
How do secondary lymphoid organs provide immunity?
(ii)
Highlight the role of spleen as an organ that provides immunity.
Marking-scheme solution
-Absorbs phosphorus from soil and passes it to the plant.
-Plants became resistant to root-borne pathogens.
-Plants become tolerant to salinity and drought.
-Overall increase in plant growth and development.
(b)
Secondary lymphoid organs provide sites for interaction of lymphocytes
with antigens , which then proliferate to become effector cells.
(ii)
Spleen :
Has lymphocytes and phagocytes , Filters blood by trapping blood borne microorganisms.
Microbes in Human WelfareMicrobes as BiofertilisersUnderstandvery_short_answermedium
More from Microbes in Human Welfare
- Assertion: Activated sludge contains large population of bacteria. Reason (R): These bacteria help in…2026 · asked 3×
- Assertion: Flocs are masses of bacteria associated with fungal filaments in secondary treatment of sewage.…2026 · asked 3×
- Study the figure given below and answer the questions that follow. Identify the figure and state its…2025 · asked 3×
- Study the given diagram of Sewage Treatment Plant (S.T.P.) and answer the questions that follow: S.T.P.…2022 · asked 3×
- Mention the common bacterium found in the anaerobic sludge during sewage treatment and also in the rumen of…2022 · asked 3×
- (i) Name the protozoan species that is responsible for causing the most serious and even fatal malarial…2026 · asked 3×
- A laboratory assistant collected three water samples, namely river water, untreated sewage water and…2026 · asked 3×
- What do you mean by activated sludge in an STP? Explain the biological treatment of the major part of the…2025 · asked 3×
CBSE Class 12 Biology past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.