Introduction:
The question asks us to compare the speed of a horse and a buffalo. We need to determine which animal runs faster between the two.

Explanation:
Here's why a horse runs faster than a buffalo:

1. Physical Characteristics:
- Horses are built for speed, with long and slender legs that allow them to cover ground quickly.
- Buffaloes, on the other hand, have shorter and stockier legs, which are better suited for plowing through dense vegetation rather than running at high speeds.

2. Muscle Composition:
- Horses have a higher percentage of fast-twitch muscle fibers, which are responsible for quick bursts of speed.
- Buffaloes have a higher percentage of slow-twitch muscle fibers, which are better suited for endurance and sustained exertion.

3. Evolutionary Adaptations:
- Horses have evolved as prey animals, which has driven them to develop speed as a survival mechanism.
- Buffaloes, on the other hand, have evolved to be more resilient and powerful, which helps them defend themselves and their herds from predators.

4. Domestication and Selective Breeding:
- Humans have selectively bred horses for centuries to enhance their speed and performance.
- Buffaloes, on the other hand, have primarily been domesticated for their strength and ability to carry heavy loads.

5. Track Record:
- Throughout history, horses have been used extensively for transportation, racing, and various equestrian activities due to their speed.
- Buffaloes, on the other hand, have primarily been used for agricultural purposes and as working animals.

Conclusion:
In conclusion, a horse runs faster than a buffalo due to its physical characteristics, muscle composition, evolutionary adaptations, selective breeding, and track record. Horses are built for speed, while buffaloes are better suited for endurance and strength.