Mammals are ureotelic but birds are obliged to be uricotelic. Explain.

Explanation

### Step-by-Step Solution:

1. **Definition of Ureotelic and Uricotelic:**
- Ureotelic organisms are those that excrete nitrogenous waste primarily in the form of urea. This is typical of mammals.
- Uricotelic organisms excrete nitrogenous waste mainly as uric acid, which is characteristic of birds.

2. **Water Availability:**
- Mammals generally have access to adequate amounts of water in their environment. This allows them to excrete waste in a liquid form (urea) dissolved in water.
...