Which of the following is an algal biofertilizer used in rice fields? MCQ with Answer and Explanation

Which of the following is an algal biofertilizer used in rice fields?
A. Nostoc
B. Azospirillum
C. Trichoderma
D. Rhizobium
Answer: Option A
Solution (By JKExamLibrary)
Nostoc is a cyanobacterium (blue-green alga) that fixes atmospheric nitrogen and is used as a biofertilizer in rice paddies. Anabaena azollae with Azolla is also common. Rhizobium is bacterial biofertilizer for legumes, Azospirillum is a free-living nitrogen-fixing bacterium. Trichoderma is a fungal biocontrol agent. BGA biofertilizers increase organic nitrogen in soil.

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Practice More Biology Questions

Question #1
Consider statements about evolution: 1. The fossil record provides evidence for evolution. 2. Embryological similarities support common ancestry. 3. Biogeography shows species distribution is random. Which are correct?
A. 1, 2 and 3
B. 2 and 3 only
C. 1 and 3 only
D. 1 and 2 only

Correct Answer: Option D


Explanation:
The fossil record shows a chronological sequence of life forms, providing direct evidence of evolutionary changes over time. Embryological similarities, such as the presence of pharyngeal slits and a notochord in early vertebrate embryos, support the idea of common ancestry. Biogeography, the study of species distribution, shows that species are not randomly distributed but are related to their geographic origins and evolutionary history. Thus, statements 1 and 2 are correct.

This question belongs to: Science Biology
Question #2
Which of the following is a primary consumer in a food chain?
A. Eagle
B. Grasshopper
C. Fungi
D. Lion

Correct Answer: Option B


Explanation:
Primary consumers are herbivores that feed directly on producers (plants). Grasshopper feeds on grass/plants, thus a primary consumer. Lion and eagle are secondary/tertiary consumers (carnivores). Fungi are decomposers. In a food chain: Grass (producer) → Grasshopper (primary consumer) → Frog (secondary consumer) → Snake (tertiary consumer) → Eagle (quaternary consumer). Energy flows unidirectionally.

This question belongs to: Science Biology
Question #3
The process of obtaining a large number of identical copies of a gene or organism is:
A. Cloning
B. Transformation
C. Hybridization
D. Mutation

Correct Answer: Option A


Explanation:
Cloning produces genetically identical copies of a DNA fragment (molecular cloning) or an entire organism (reproductive cloning). Hybridization is crossing different varieties, mutation is change in DNA, transformation is DNA uptake.

This question belongs to: Science Biology