Explanation:

- Ribosomes: These are present in animal cells. They are the sites where protein synthesis occurs.

- Plastids: These are not found in animal cells. Plastids, such as chloroplasts, are found in plant cells and are involved in photosynthesis.

- Lysosomes: These are present in animal cells. They contain enzymes that break down waste materials and cellular debris.

- Mitochondria: These are present in animal cells. Mitochondria are known as the powerhouses of the cell because they generate the cell's energy.

Correct Answer: Option 2: Plastids