Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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21.

Leghaemoglobin helps in

  • imparting colour to floral petals

  • protecting nitrogenase from O2

  • destroying bacteria

  • transport of food in plants


B.

protecting nitrogenase from O2

Leghaemoglobin is a pinkish pigment present inside the root nodules of nitrogen fixing plants like legumes. It is an oxygen scavenger and is related to blood pigment haemoglobin. It protects nitrogen fixing enzyme nitrogenase from oxygen. The most important bacteria present inside the nodules is Rhizobium.


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22.

Which among the following is a rootless plant?

  • Nymphaea

  • Sagittaria

  • Ceratophyllum

  • Vallisneria


23.

Composite fruit develops from

  • single ovary

  • inflorescence

  • apocaropous ovary

  • pericarp


24.

Cocoa is the plant from which chocolate is made. Which part is used to extract it?

  • Flower

  • Fruits

  • Seeds

  • Bark


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25.

Assertion : Astigmatism is due to uneven curvature of lens.

Reason : It is treated with cylindrical lenses.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


26.

Assertion : Blood coagulate in uninjured blood vessels.

Reason : Uninjured blood vessels release an anticoagulant heparin.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


27.

Assertion : Smaller the organism higher is the rate of metabolism per gram weight.

Reason : The heart rate of a six month old baby is much lower than that of an old person.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


28.

Assertion : Torison can be seen in ctenidium.

Reason : Ctenidium acts as the respiratory organ.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


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29.

Assertion : Secreting hypotonic urine is effective in reducing urinary loss of water.

Reason : Hypotonic urine is more concentrated and higher in osmotic pressure than the blood.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


30.

Assertion : Aldosterone is a steroid hormone and is important in the control of sodium and potassium ion concentration in mammals.

Reason : It upgrades sodium ion concentration in the ECF by promoting reabsorption of sodium ions from renal tubules and excretion of potassium ions in urine.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


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