Explain why a single-celled organism such as Amoeba can carry out all life processes without needing specialised cells.

A single cell can perform all life processes because it contains all the necessary organelles and enzymes in one place.

1. The amoeba’s small size means that substances such as oxygen, food and waste can move across its membrane by diffusion, so it does not need specialised transport systems.
2. Because all functions occur in the same cell, there is no need for a division of labour – the cell can feed, respire, excrete and reproduce without specialised cells.
3. In multicellular organisms, cells become specialised because a single cell cannot efficiently carry out all the functions required for the whole organism; specialised cells allow division of labour and increased efficiency.
4. Thus, the amoeba’s small size and single‑cell structure allow it to carry out all life processes without specialised cells.