How are waste products excreted in amoeba?

How are waste products excreted in amoeba ?
A. 1) Special excretory organs are absent in unicellular organisms like amoeba.
2) Amoeba possesses osmoregulatory organelle called contractile vacuole.
3) It collects water and wastes from the body, swells up, reaches the surface and bursts to release its content to outside.
4) The main excretion takes place through body surface by simple diffusion.
5) The waste material carbon dioxide is removed by diffusion through the cell membrane.