Plenty of algal bloom is observed in a pond in your locality.(a)

Subject

Biology

Class

CBSE Class 12

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 Multiple Choice QuestionsShort Answer Type

1.

Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.

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2.

State the fate of a pair of autosomes during gamete formation.

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3.

What role does an individual organism play as per Darwin’s theory of natural selection?

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4.

Suggest a method to ensure an anamnestic response in humans.

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5.

What is biopiracy?

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6.

A mature embryo sac in a flowering plant may possess 7-cells, but 8-nuclei. Explain with the help of a diagram only.

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7.

Mention the evolutionary significance of the following organisms:

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8.

In an agricultural field, there is a prevalence of the following organisms and crop diseases which are affecting the crop yield badly:
(a) White rust (b) Leaf and stripe rust
(c) Black rot (d) Jussids
Recommend the varieties of crops the farmers should grow to get rid of the existing problem and thus, improve the crop yield.

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9.

How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output?

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10.

Plenty of algal bloom is observed in a pond in your locality.
(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure.


(a) The presence of large amounts of nutrients in water leads to algal bloom. These nutrients (nitrogen and phosphorus) are added to water bodies from fertilisers that get issolved in soil and are washed off by water bodies. Algal bloom affects the quality of water in the
following ways:
(i) It causes deterioration of water quality making it unfit to use.
(ii) Eutrophication (natural ageing of water bodies) is accelerated, resulting in hypoxic conditions (i.e. low oxygen), killing off the aquatic diversity.

(b) To prevent the algal bloom, the farmers instead of using chemical nutrients must start using natural products like manures produced using vermicomposting. Biodegradable materials should be used, that are readily decomposed and are phosphate free. Awareness should be created among people about the effects of dumping waste in water bodies.

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