Which of the following organisms invaded the land first?

Options

A. Plants
B. Coelacanth
C. Amphibians
D. Reptiles

Answer

To determine which organism invaded the land first, we need to analyze the geological time scale and the periods in which each of the given organisms evolved.

### Step-by-Step Solution:

1. **Identify the Organisms and Their Periods**:
- **Plants**: Evolved in the Ordovician period.
- **Silacanth**: A type of fish that evolved in the Triassic period.
- **Amphibia**: Evolved in the Devonian period.
- **Reptiles**: Evolved in the Carboniferous period.

2. **Arrange the Organisms by Their Evolutionary Periods**:
- The Ordovician period is the earliest among the periods mentioned for the organisms listed.
- Following the Ordovician, the Devonian period comes next (for Amphibia), then the Carboniferous period (for Reptiles), and finally the Triassic period (for Silacanth).

3. **Determine the First Organism to Invade Land**:
- Since plants evolved in the Ordovician period, they were the first organisms to invade land before any of the other listed organisms.

4. **Conclusion**:
- Therefore, the organism that invaded the land first among the options provided is **Plants**.

### Final Answer:
**Plants**