Q. No.
The most toxic nitrogenous metabolic waste product is:
| 1. ammonia | 2. urea |
| 3. uric acid | 4. methane |
Uricotelic mode of passing out nitrogenous wastes is found in
| 1. | reptiles and bird | 2. | birds and annelids |
| 3. | amphibians and reptiles | 4. | insects and amphibians |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
| Assertion (A): | Many amphibians excrete mainly ammonia when they are aquatic tadpoles and switch largely to urea excretion when they become land dwelling adults. |
| Reason (R): | The main disadvantage of urea is its energy cost and the main advantage is its low toxicity. |
In the light of the above statements choose the correct answer from the options given below
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
All the following animals are uricotelic except:
| 1. Reptiles | 2. Land snails |
| 3. Birds | 4. Marine fishes |
Protonephridia are the excretory structures in all the following except:
| 1. Planaria | 2. Rotifers |
| 3. Amphioxus | 4. Prawns |
| Column I [Organism] |
Column II [Osmoregulatory and excretory structure] |
||
| A | Flatworms, rotifers, Amphioxus | P | Protonephridia |
| B | Earthworm | Q | Nephridia |
| C | Insects | R | Malpighian tubule |
| D | Prawn | S | Green gland or antennal gland |
| A | B | C | D | |
| 1. | P | Q | R | S |
| 2. | Q | R | S | P |
| 3. | R | S | P | Q |
| 4. | S | P | Q | R |
In majority of the nephrons, the loop of Henle:
1. is absent
2. extends only a little into the medulla
3. extends deep into the medulla
4. is associated with a highly developed vasa recta
Juxtamedullary nephrons:
1. are more common than cortical nephrons
2. do not have a well developed vasa recta associated with them
3. play a very important role in concentration of urine
4. produce angiotensinogen
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