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 Multiple Choice QuestionsMultiple Choice Questions

71.

Heterocysts in Anabaena is helpful in

  • secondary growth

  • nitrogen-fixation

  • ion uptake

  • gaseous exchange


72.

The statement given below are the deficiency symptoms of a certain element. Identify the element with the help of options that follow.

I. Stunted growth

II. Tissue necrosis

III. Curling appear first in young leaves

IV. Premature flower abscission

Choose the correct option

  • magnesium

  • boron

  • calcium

  • nitrogen


73.

The nitrifying bacteria that convert the ammonia to nitrates are

  • Nitrosomonas and Nitrobacter

  • Azotobacter

  • Rhizobium sp.

  • Thiobacillus denitrificans


74.

Insectivorous plant is

  • Cuscuta

  • Drosera

  • Striga

  • None of the above


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75.

Nodules with nitrogen-fixing bacteria are found in

  • cotton

  • gram

  • mustard

  • wheat


76.

Mycorrhiza is an example of

  • endoparasitism

  • decomposers

  • symbiotic relationship

  • ectoparasitism


77.

A metal ion involved in stomatal regulation is :

  • iron

  • potassium

  • zinc

  • magnesium


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78.

The plant ash is an indication of :

  • organic matter of plant

  • waste product

  • mineral salts absorbed by plants

  • none of these


C.

mineral salts absorbed by plants

The ash that is left after burning any dry part of the plant in a crucible, contains only mineral elements and is called plant ash. If dried plant parts are heated in silica crucible at 600°C, all organic substance vaporize and the remaining plant ash contains only inorganic substances or absorbed mineral elements.


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79.

Hydroponics is

  • cultivation of plants in water

  • growth of plants towards water

  • growth of plants away from water

  • soil less cultivation of plants


80.

When one element is involved in opening and closing of stomata, the other helps to maintain the ribosome  structure. They are

  • Potassium and calcium

  • Phosphorus and sulphur

  • Potassium and magnesium

  • Iron and magnesium

  • Iron and magnesium


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