Question

if an organelle is no longer functioning, what will break it down? ribosome lysosome vacuole

Explanation:

Lysosomes are membrane - bound organelles that contain digestive enzymes. These enzymes can break down various substances, including non - functioning organelles. Ribosomes are involved in protein synthesis, and vacuoles are mainly for storage (in plant cells, they can also have some roles in maintaining turgor pressure, but not in breaking down organelles).

Answer:

Lysosome.