It is almost certainly a program, not a description, a series of steps that directs a handful of embryonic cells into progressively more specialized tissues.

But mosses are not vascular - that is, they lack developed roots and specialized tissues for transporting water and nutrients around the plant.

Many considered the endothelium a specialized epithelial tissue.

Even fruit flies, which have no bones, use them to set off the growth of specialized tissues like wings.

Once plants colonized land however, they required specialized tissues to absorb water efficiently, and also to anchor themselves to the land.

Cartilage is the specialized tissue that serves as a buffer or cushion at joints.

Thus, on the one hand the system provides a highly adaptable basis for the culture of adherent cells and the generation of specialized tissues.

To meet the individual requirements of specialized tissues a variety of perfusion culture containers was constructed (Fig. 3).

From single cells to specialized tissues in perfusion culture.

Adult stem cells are unspecialized cells that occur in specialized tissues.