Here's why:

* Chloroplasts are the sites of photosynthesis in plant cells. They contain chlorophyll, the pigment that absorbs light energy to convert it into chemical energy. Animal cells do not need to perform photosynthesis as they obtain energy from consuming other organisms.

Let's look at the other options:

* Ribosomes are essential for protein synthesis and are found in both plant and animal cells.

* Mitochondria are the powerhouses of the cell, responsible for cellular respiration in both plant and animal cells.

* Golgi apparatus processes and packages proteins and lipids in both plant and animal cells.

Therefore, the only component uniquely found in plant cells and not animal cells is chloroplasts.