Final answer:
In animal cells, the degradation of worn-out organelles occurs in lysosomes.
Step-by-step explanation:
In animal cells, the degradation of worn-out organelles occurs in lysosomes. Lysosomes are organelles surrounded by a membrane that contain hydrolytic enzymes responsible for breaking down various cellular components, including old organelles. These enzymes are active at a lower pH than the cytoplasm, making lysosomes more acidic.