Organisms present in this biosphere show great diversity in size, structure, and mode of life. In spite of this diversity, they show unity in their basic stricture and processes. The body of an organism is formed of one or many cells. All cells are composed of a semifluid material, the cytoplasm which is enclosed by a thin coat called plasma membrane. The different subcellular components called organelles, viz., nucleus, mitochondria, Golgi bodies, chloroplast, lysosomes, etc are present in the cells. Striking similarities can be observed in the organelles of the cells of diverse organisms. Thus in spite of diversity, all organisms show unity in certain basic features. Read more>>