The main groups of unicellular organisms are bacteria<span>, </span>archaea<span>, </span>protozoa<span>, unicellular </span>algae<span>, and unicellular </span>fungi<span>. </span>
In order to increase the rate of diffusion of materials in and out of the cell, the following modification can be done to the cell:
1. the shape of the cell can be changed to one that has high surface area to volume ration, for example sphere.
2.The cell can also divide into two in order to increase the surface area to volume ratio.
