Here's why:

* Photosynthesis: Chloroplasts are the sites of photosynthesis, the process where plants convert light energy into chemical energy.

* Carbon Dioxide's Role: Carbon dioxide is one of the key ingredients in photosynthesis. It's combined with water to produce glucose (sugar) and oxygen.

* Absorption: The chloroplasts have openings called stomata on the leaves that allow carbon dioxide to enter the plant.

Let me know if you have any other questions!