A tissue is a group of similar cells and their intercellular materials in a discrete region of an organ performing a specific function. <span>There
are five levels of organization and these are the cells, tissues, organs, organ
systems and organism. The most complex is the organism having the rest of the
organization in it and the least complex is the cell, the basic unit of
structure. The human body tissue is an organized group of cells that is formed to create a muscle or an organ. There are four types of human body tissue: muscle, epithelial, connective and nervous tissue. Each function according to how they are grouped.</span>
All the domestic breeds of dogs that we are familiar with, from chihuahuas to pit bulls, are the same species: Canis lupus<span> familiaris. In fact, our dogs are a subspecies of </span>Canis lupus<span>, or ->*wolf*<-</span>
