Melanin provides pigmentation to the skin and it also provides UV ray protection (which is its role in the epidermis).
<span>Root hairs and all active transport mineral ions are used by plants to enable water absorption. The route of the movement of water inside the root would be illustrated through this sequence:Epidermis (outside layer of the roots) --> cortex (ground tissue layer just between the epidermis and the root's vascular tissue) --> endodermis(a layer outside the vascular tissue;responsible for mineral uptake of plants) --> stele( tissues combined inside the cortex) --> xylem (can be primary and secondary, both originates from provascular tissue and vascular cambium,maturing to its inside, respectively) --> phloem (can be primary and secondary too, both originates from provascular tissue and vascular cambium,maturing to its outside, respectively --> cambium(a meristem originating from an apical meristem, gives rise to secondary xylem and secondary phloem. </span>
Microtubules are tiny, hollow, bead-like tubular structures that help cells maintain their shape. Along with microfilaments and intermediate filaments, they form the cytoskeleton of the cell, as well as participate in a variety of motor functions for the cell.
The similarity between directional and disruptive is that both are types of selection on polygenic traits in which the curve shift away from the middle.
The different between disruptive and directional is in disruptive move toward both ends . And in directional, the curve shift toward one end.
