Here's why:

* Chloroplasts are organelles found in plant cells and some algae. They are responsible for photosynthesis, the process of converting sunlight into energy.

* Chlorophyll, the pigment that gives plants their green color, is located within chloroplasts.

* Under a microscope, chloroplasts appear as small, green, oval-shaped structures.

Therefore, the cell you're describing is most likely a plant cell.