Aphylogenetic tree:
a. classifies all plant species based on their habitats.
b. diagrams the evolutionary history of a particular group of organisms.
c. is based on binomial nomenclature.
d. only catalogues fossil plants .
e. only uses genome sequencing data

B. diagrams the evolutionary history of a particular group of organisms.

Explanation:

Phylogenetic trees represent hypotheses about the evolutionary relationships between a group of organisms.

A phylogenetic tree with the morphological (body shape), biochemical, behavioral or molecular characteristics of species or other groups can be constructed.

When building a tree, we organize the species into nested groups based on shared derived characters (characteristics different from those of the group's ancestor).

Gene or protein sequences can be compared between species and used to build phylogenetic trees. Nearby species usually have few differences in their sequences, while less related ones tend to have more.

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.    

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.