Here's a breakdown:

* Chloroplasts are the sites of photosynthesis. They contain the green pigment chlorophyll, which absorbs light energy from the sun.

* This energy is used to convert carbon dioxide and water into glucose (sugar), which is the plant's food, and oxygen.

* This process is called photosynthesis and is essential for life on Earth as it produces oxygen and the energy base for most food chains.

So, while other organelles play important roles in plant life, the chloroplast is the one that makes the food from sunlight.