EVOLUTION OF HORSE

Options

A. Lengthening of limbs and increases in size
B. Progressive loss of digits and lentheningof retained digits causing shifting of soft footed to paddil,e footed.
C. Increased complexity of molars and molarisation of premolars.
D. All the above.

Answer

### Step-by-Step Solution for the Evolution of Horse

1. **Introduction to Horse Evolution**:
- The evolution of horses is a gradual process that has taken place over millions of years. It involves changes in physical structure and adaptations to their environment.

2. **Ancestral Horses**:
- The evolution of modern horses can be traced back to ancestral species such as **Hyracotherium** and **Ohippus**. These early horses had distinct characteristics that differ from modern horses.

3. **Key Changes in Horse Evolution**:
- **Lengthening of Limbs**: Over time, horses developed longer limbs which allowed for faster running and better adaptation to open environments.
- **Progressive Loss of Digits**: Early horses had multiple toes, but through evolution, they lost these digits, resulting in the development of a single hoof. This change helped in better support and speed.
- **Paddle-Footed Adaptation**: The evolution led to the formation of a hoof structure, which is more efficient for running on various terrains.
- **Increased Complexity of Molars**: The molars of modern horses became more complex, allowing them to grind tougher plant materials effectively. Premolars also evolved to support this function.

4. **Conclusion**:
- All the mentioned evolutionary changes are correct and contribute to the overall evolution of horses. Therefore, the correct answer to the question is **"all of the above."**