Question

Nitrogenous waste products are eliminated mainly as

• A. Urea in tadpole as well as in adult frog
• B. Urea in tadpoles and ammonia in adult frog
• C. Urea in tadpole and uric acid in the adult frog.
• D. Urea in adult frogs and ammonia in tadpoles.

Answer 1

The correct option is D

Urea in adult frogs and ammonia in tadpoles.

The correct option is D.
Explanation of the correct option:

1. The nitrogen molecules that organisms use to get rid of extra nitrogen are referred to as nitrogenous wastes or nitrogen wastes.
2. They are creatinine, ammonia, urea, and uric acid.
3. These chemicals are all created by the metabolism of proteins.
4. Different animals emit nitrogenous waste in different ways.
5. These include urea, ammonia, and uric acid, among others.
6. As a result, these creatures are known as ureotelic animals.
7. Animals classified as ureotelic excrete excess nitrogen as urea, which requires less water than ammonia.
8. Humans and cartilaginous fish are two examples.
9. Tadpoles release ammonia to adapt to their aquatic habitat, whereas frogs release urea to adjust to their terrestrial lifestyle.

Explanation of the incorrect options:
Option A:

1. Before metamorphosing, tadpoles excrete ammonia; however, during the metamorphic transitions that prepare them for terrestrial invasion, urea replaces ammonia as the excretory end product.

Option B:

1. Before metamorphosing, tadpoles excrete ammonia; however, during the metamorphic transitions that prepare them for terrestrial invasion, urea replaces ammonia as the excretory end product.
2. Since ammonia is very soluble in water, nitrogenous waste products are expelled as ammonia by aquatic organisms like tadpoles of frogs.
3. These wastes are expelled by terrestrial animals, such as adult frogs, as urea.

Option C:

1. Because urea is less poisonous than ammonia and may be concentrated in the urine and discharged at a slower pace, adult frogs are ureotelic.
2. Uric acid is the kind of nitrogenous waste that birds emit.

Final answer: Nitrogenous waste products are eliminated mainly as urea in adult frogs and ammonia in tadpoles.