It's all of the above. Homeostasis is the function the body does to make sure it's working properly.
Explanation:
In amoeba respiration takes place through its cell membrane also called the plasma membrane. Amoeba gets oxygen gas dissolved in surrounding water through its plasma membrane by the process of diffusion. The oxygen gas diffused inside the body is used up by the amoeba. In the body, the oxygen gas absorbed is used to break down the complex food material into simple molecules. During these metabolic reactions in the body of amoeba, the oxygen gas is converted into carbon dioxide gas. The carbon dioxide gas is also liberated in the surrounding water through the same process of diffusion.
Since amoeba needs oxygen for respiration, the type of respiration is aerobic respiration.
Isotonic solution.
Since it has the same salt concentration as the cell the solution is neither hypotonic or hypertonic.