Leghaemoglobin helps in
imparting colour to floral petals
protecting nitrogenase from O2
destroying bacteria
transport of food in plants
Cocoa is the plant from which chocolate is made. Which part is used to extract it?
Flower
Fruits
Seeds
Bark
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
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.
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
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
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
D.
If both assertion and reason are false
When there is a threat of excessive water loss from the body of the animal, then the urine excreted needs to be hypertonic and not hypotonic. This is due to the reason as excessive water loss from the body possess the threat of a rise in osmoconcentration of the blood. Since hypertonic urine is more concentrated and higher in osmotic pressure than the blood, therefore it helps in reducing the loss of water with urine.
Mammals and birds can excrete hypertonic urine which is more concentrated than their blood. For this, an isotonic glomerular filtrate is first filtered into the Bowman's capsules of nephrons in kidneys. The tubules then reabsorb a large volume of water from the glomerular filtrate not accompanied by the reabsorption of proportionate amounts of solutes. This leaves the urine more concentrated than the blood which is very effective in reducing the urinary loss of water.
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