Answer:
Explanation: In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into or out of, the cell by moving down it.
The question must refer to the modern classification system in biology.
It started with the work of Linnaeus - so its early version can be called a Linnaean classification - but right now it has been expanded and changed to fit the evolutionary relationships between the species - which is the best description, i.e. the answer is "it is based on the evolutionary relationship of the species"
The combination of drought and poor land use practice created the the dust bowl.