Match the items in Column 'A' and Column 'B' and c – Class 12 Biology

NCERT Exemplar · Q19

Q. Match the items in Column 'A' and Column 'B' and choose correct answer. Column I — Column II A. Lady bird — i. Methanobacterium B. Mycorrhiza — ii. Trichoderma C. Biological control — iii. Aphids D. Biogas — iv. Glomus The correct answer is:

(a) A-ii, B-iv, C-iii, D-i

(b) A-iii, B-iv, C-ii, D-i

(d) A-iii, B-ii, C-i, D-iv

Rajasthan RbseMCQ· 1mImportance★★★★★

43% · 34/80 Questions

🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Concept understanding — Biofertilizers Biopesticides

Imagine you have a garden. You want your plants to grow strong and healthy, and you also want to keep pests away. There are two main ways to do this: one is with harsh chemicals (chemical fertilizers and pesticides), and the other is with living things or natural substances. Biofertilizers and biopesticides are the second way — they are nature’s own tools for farming.

Let’s start with biofertilizers. Think of them as "living manure." A chemical fertilizer is like giving a plant a direct shot of nutrients — it works fast but can burn the soil over time. A biofertilizer, on the other hand, is a preparation containing live microorganisms (like bacteria, fungi, or algae) that help the plant get nutrients from the soil or air. For example, certain bacteria can take nitrogen from the air and convert it into a form the plant can use. The plant doesn’t get fed directly; instead, the biofertilizer helps the soil become richer and more fertile naturally.

Note

The NCERT textbook (Class 12 Biology, Chapter 10) defines biofertilizers as organisms that enrich the nutrient quality of the soil. The main examples are Rhizobium (a bacterium that lives in root nodules of legumes and fixes nitrogen), Azospirillum and Azotobacter (free-living nitrogen-fixing bacteria), and blue-green algae (like Anabaena) which also fix nitrogen.

Now, biopesticides. These are living organisms or natural substances that control pests — insects, fungi, weeds, etc. — without using synthetic chemicals. Instead of spraying a poison that kills everything (good and bad bugs alike), a biopesticide might use a specific bacterium that only harms a particular caterpillar, or a fungus that attacks a weed. The most famous example is Bacillus thuringiensis (often called Bt), a bacterium that produces a protein toxic to certain insect larvae but harmless to humans, animals, and most other insects.

Important

The key difference between chemical and biological agents: Biofertilizers and biopesticides are renewable, eco-friendly, and do not leave toxic residues in the soil or water. They are a cornerstone of sustainable agriculture — farming that can continue for generations without destroying the land.

Why does this matter for a commerce or humanities student? Because agriculture is not just about biology — it’s about economics, policy, and human health. Chemical fertilizers and pesticides are expensive to produce, can pollute groundwater, and their overuse leads to "superpests" that become resistant. Biofertilizers and biopesticides are often cheaper in the long run, safer for farm workers, and help maintain soil health. Governments around the world (including India) promote them through subsidies and organic farming schemes. Understanding them helps you see why "organic" food costs more, why some farmers switch to natural methods, and how environmental regulations work.

Here’s a quick summary of the main types you should know (from NCERT):

Biofertilizers:
- Rhizobium (symbiotic with legumes) …

Start your 14-day free trial to unlock the full solution →

Each organism in Column I performs a specific ecological or agricultural role: ladybirds control aphids, mycorrhizae involve Glomus, Trichoderma is used in biological control, and Methanobacterium produces biogas.

The question asks you to connect organisms or processes with their correct biological partners or functions, drawing on fundamental concepts in microbiology and applied biology that appear throughout NCERT's treatment of microbes in human welfare.

Ladybird beetles are classic examples of biological pest control agents. These small, often brightly colored insects are voracious predators of aphids—tiny sap-sucking pests that damage crops. A single ladybird can consume hundreds of aphids in its lifetime, making it a farmer's ally in integrated pest management. The NCERT textbook highlights ladybirds specifically in the context of controlling aphid populations without chemical pesticides. So A matches with iii (Aphids).

Mycorrhiza refers to the symbiotic association between fungi and plant roots. The fungal partner helps the plant absorb water and minerals (especially phosphorus) from the soil, while the plant supplies the fungus with carbohydrates. Glomus is a genus of arbuscular mycorrhizal fungi—one of the most widespread and agriculturally important mycorrhizal types. NCERT explicitly mentions Glomus as a mycorrhizal fungus that forms beneficial associations with plant roots. Thus B matches with iv (Glomus).

Biological control involves using living organisms to suppress pest populations. Trichoderma is a genus of free-living fungi that acts as a biocontrol agent against several plant pathogens. It parasitizes other fungi, competes for nutrients, and produces antibiotics that inhibit disease-causing organisms in the soil. The textbook discusses Trichoderma species in the context of biopesticides and organic farming. Therefore C matches with ii (Trichoderma). …

Start your 14-day free trial to unlock the full solution →

A different angle: sort the 8 items into 2 functional roles BEFORE matching letters to numbers.

Role	Items
Pest/pathogen control agents	Lady bird (predator), Biological control (the category itself), Trichoderma (biocontrol fungus)
Nutrient-providing symbionts / gas producers	Mycorrhiza (nutrient symbiosis), Glomus (mycorrhizal fungus), Biogas (energy production), Methanobacterium (methanogen)

Start your 14-day free trial to unlock the full solution →

←Previous questionQ18 — Activated sludge should have the ability to settle quickly so that it …→Next questionQ20 — Why does 'Swiss cheese' have big holes?

Q.Match the items in Column 'A' and Column 'B' and choose correct answer. Column I — Column II A. Lady bird — i. Methanobacterium B. Mycorrhiza — ii. Trichoderma C. Biological control — iii. Aphids D. Biogas — iv. Glomus The correct answer is:

🎓Unlock everything free for 14 days

Q.Match the items in Column 'A' and Column 'B' and choose correct answer.
Column I — Column II
A. Lady bird — i. Methanobacterium
B. Mycorrhiza — ii. Trichoderma
C. Biological control — iii. Aphids
D. Biogas — iv. Glomus
The correct answer is:

Unlock everything free for 14 days