The substances urea, uric acid, and ammonia share some important characteristics, particularly in their role in the body. Let's break down the options:
Key Characteristics
- Nitrogenous Wastes: All three are indeed nitrogenous wastes produced from the metabolism of proteins.
- Water Requirement: Urea and uric acid require less water for excretion compared to ammonia, which is highly soluble and needs a lot of water.
- Toxicity: Ammonia is the most toxic, while urea is less toxic, and uric acid is the least toxic.
- Production Site: Urea and uric acid are produced in the liver, while ammonia is primarily produced in the body but can be converted to urea in the liver.
Evaluating the Options
Now, let's analyze the answer choices:
- (a) i, ii and iv - Incorrect, as they do not all require a large amount of water.
- (b) i only - This is true, but it doesn't encompass all relevant information.
- (c) i and iii - While they are nitrogenous wastes, they are not equally toxic.
- (d) i and iv - This is correct as they are all nitrogenous wastes and produced in the kidneys.
Correct Answer
The best choice is (d) i and iv, as it accurately reflects their nature as nitrogenous wastes and their production in the kidneys.
