Unicellular organisms excrete waste by osmosis diffusion active transport all of the above

The answer is  diffusion.

Explanation: Unicellular organisms excrete waste by diffusion.

Unicellular organisms are organisms that have only one cell. They are called single cell organisms because all their life processes such as reproduction, feeding, digestion, and excretion, occur in only one cell. An example of unicellular organism is paramecium.

Diffusion is the inactive movement of molecules  from the region of higher concentration to the region of lower concentration.

Diffusion

Explanation:

The unicellular organisms are performing all their physiological activities in a single cell. They are mostly aquatic organism. The water constantly move into and out of their cell. The water enters into their cell by the process of osmosis. When there is excess water stored in the body, this is absorbed by the contractile vacuoles present in it. This maintains the water balance of their body and this process is known as the osmotic balance.

But when the unicellular organisms excrete, they withdraw nitrogenous wastes i.e. ammonia. This waste consists of small particles of ammonia which are aggregated from other areas of the cell and expel out of the membrane. This process is called diffusion.

Diffusion is the process when the solute/ small solid particles move from high concentration to lower concentration. These waste materials stored in the body and passes out through cell membrane to the surrounding environment by diffusion.

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