Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Explanation

### Step-by-Step Solution:

1. **Understanding Warm-Blooded Animals**:
- Mammals and birds are classified as warm-blooded (endothermic) animals. This means they can maintain a constant body temperature regardless of the external environment.

2. **Importance of Constant Temperature**:
- Maintaining a constant body temperature is crucial for the proper functioning of metabolic processes. If the body temperature fluctuates significantly, it can disrupt these processes and potentially harm the organism.

...