Cell

Cells are the structural and functional units of all living organisms. It is also described as the smallest unit of life. Every organism cannot exist without cell because the functionality of all living organism depends so much on how the cell works and functions within the tissues, organs and the entire body system especially in human being. Though, some organisms, such as bacteria, are unicellular, consisting of a single cell without tissues, organs and system. Cell naturally is an amazing world unto itself: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Even more amazing is that each cell stores its own set of instructions for carrying out each of these activities.