Here's why:

* Chloroplasts are the organelles responsible for photosynthesis, the process by which plants convert light energy into chemical energy.

* Leaf cells are the primary site of photosynthesis in plants, so they have chloroplasts.

* Other cell types, like root cells, don't need to perform photosynthesis and therefore don't have chloroplasts.

Let me know if you'd like to learn more about chloroplasts or photosynthesis!