Which of the following helps amoeba in gas exchange?

Amoeba is a single-celled organism that lacks specialized respiratory structures like lungs and gills. It instead relies on its cell membrane to conduct the gas exchange. 

The cell membrane is selectively permeable, allowing gases such as oxygen and carbon dioxide to diffuse across it. 

The concentration gradient of these gases drives the movement of oxygen into the cell and the removal of carbon dioxide, thereby maintaining the cell's gas balance. 

This simple gas exchange mechanism is sufficient to meet the needs of a single-celled organism with a low metabolic rate, such as an amoeba.