Typical general design of multicellular organism

Any multicellular organism consists of many cells of different types, which form two or three main layers in the body. Any Metazoa has, probably, next general plan of construction in ontogenesis and evolution: border layers of cells, and then tissues (epithelium’s, mesothelium’s, endothelium’s) are united by their derivatives in one or another form, including intermediate cells or their congestion, systems such as mesoglea, mesoblast, connective tissues. Complication of inner border structure comes during individual development in connection with external border form (different general and local deformations) in the result (by means of) uneven growth and differentiation of their parts with two- or three-layer structure. This is no change the general design (general plan of border structure) of animal, the two- or three-layer.