No, cladograms deal with living species.
The answer is; desertification
Topsoil is usually the riches soil in terms of nutrient is important in support of plant vegetation. It is rich because it contains humus and other decomposed materials that recycle nutrients. When the topsoil is washed away, the local region becomes barren in that it cannot support vegetation. This causes the area to turn into a desert.
The xylem cells or vessel!
Well, It's either OCD or PTSD... Depending on what the person has gone through in the past, it could be PTSD, PTSD would be caused by being traumatized by something, Like if I got robbed, i would check if my doors are locked.
