Cells are the structure directly below tissues in the hierarchical organization of life.
Explanation:
A cell is defined as a structural, biological and functional unit of life. A cell is known as the smallest unit. A cell is mainly consisted of cytoplsam covered with membrane. It consist of protein and nucleic acid.
Epithelial cells is the thin layer also known as endothelium . This epithelium cell is fully covered all over the body. It performs various of function such as excretion, absorption,protection,diffusion, secretion as well as sensory reception. These tissues cover all the organs.
