Focus Area 2021 | Questions and Answers | Plus One Zoology | Excretory Products and their Elimination


1.   Fish: ammonotelic:  

      Cockroach:……….. (Score ½)

Answer: Uricotelic

2.   Classify the following animals on the basis of the mode of nitrogenous waste excretion in the table given below (Score 2)

Mammals, Birds, Bony fishes, Reptiles, Terrestrial amphibians, Aquatic amphibians











Bony fishes

Aquatic amphibians


Terrestrial amphibians



3.   Terrestrial animals are either ureotelic or uricotelic not ammonotelic. Evaluate the statement. (Score 2)


NH3 is highly toxic. So, excretion needs excess water. So ammonotelism is found in aquatic animals. For the excretion of urea and uric acid, a very little quantity of water is needed. So terrestrial animals are either ureotelic or uricotelic.

4.   Observe the figure given below and answer the questions. (Score 2)

a.  Write the name of the figure.

b.  Name the labelled part (A) and (B).


(a) Malpighian body (renal corpuscle).

(b) A= Glomerulus, B= Bowman’s capsule

5.   Complete the flow chart showing the regulation of kidney functioning by Juxta Glomerular Apparatus and Adrenal Cortex. (Score 2)


    A= Renin

    B= Angiotensin I

    C= Aldosterone

    D= Rise in GFR

6.   State whether the following statements are true/false. If false, correct it.

a.  ADH prevents diuresis.

b.  ANF causes an increase in blood pressure.

c.  Angiotensin-l activate adrenal cortex to release aldosterone.

d.  Aldosterone causes the reabsorption of Na+ and water from the distal part of the renal tubule.


(a) True

(b) False. ANF decreases blood pressure.

(c) False. Angiotensin-II activates the adrenal cortex to release aldosterone.

(d) True.

7.   a) Expand GFR.
Even though GFR in a healthy person is 180 liters per day, the amount of urine released Per day is only about 1.5 litres. Give a reason. (Score 2)


(a) Glomerular Filtration Rate.

(b) About 99% of the filtrate is reabsorbed by the renal tubules (Tubular reabsorption).

8.   a) Write the significance of reabsorption in urine formation. (Score 2)
b) Of the following substances which one is reabsorbed by active transport?

Glucose, Nitrogenous waste, Water


(a) Conservation of water and useful substances. The concentration of urine.

(b) Glucose

9.   “The functioning of human kidney is efficiently monitored and regulated by hormonal actions of hypothalamus, pituitary, JGA and to a certain extent by heart”

        a) Do you agree with this statement?
        b) Justify your answer with suitable reasons. (Score 2)


(a) Yes.

(b) When body fluid level decreases, the osmoreceptors stimulate the hypothalamus to release ADH from the neurohypophysis. It stimulates water reabsorption.

A fall in GFR activates the JG cells to release renin.

An increase in blood flow to the atria of the heart causes the release of Atrial Natriuretic Factor (ANF). It causes vasodilation to decrease blood pressure.

10. Complete the following sentences. (Score 2)

    (a) Accumulation of urea in the blood due to malfunction of kidney ……………
    (b) ……………… is the inflammation of glomeruli.
    (c) Angiotensin II activates the adrenal cortex to release ……………
    (d) The epithelial cells called …………. of the Bowman’s capsule are arranged in an intricate manner leaving some minute spaces called filtration slits (slit pores).


(a) Uremia

(b) Glomerulonephritis.

(c) Aldosterone

(d) Podocytes

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