are some of the smallest organisms around. All living things consist of , and yet they are invisible to the naked eye. How and why are they so small? Well, are the basic structural and functional units of life. As life on earth has evolved into organisms of different species and living things, two basic laws of nature have dictated why have remained so small. One is simply, shorter is faster. This is true as far as diffusion is concerned and also in terms of chemical and electrical movement. By minimizing the distance between a cell’s n ....