Unicellular organisms remove the waste material from their body by

In unicellular organisms, e.g. amoeba, paramecium, there are no separate excretory organs. They excrete out waste through general body surface through simple diffusion. The biological process involved in the removal of harmful metabolic wastes from the body is called excretion. These metabolic wastes include the nitrogenous materials. Different organisms use varied strategies for this. Many unicellular organisms remove these wastes by simple diffusion. Diffusion is the movement of particles from the region of high concentration to the region of low concentration. Filtration – It is a physical process used to separate solids from liquid or gases. Reabsorption occurs in kidney, which selectively reabsorbs substances like glucose, protein, sodium, which had already been secreted in the renal tubule. These reabsorbed substances return to blood. Translocation is the transport of soluble products of photosynthesis by the food conducting tissues, called phloem. Therefore, simple diffusion is the correct answer.