Which component of roots is a differentiating region?
A. Stele
B. Cork

if im mistaken, is it not apical meristem?

A. Stele

Explanation:

The stele is located in the region of differentiation. "It is found at the center of the root, bound by the pericycle. It contains the vascular tissues, xylem, phloem, and cambium."

Cork and apical meristems are undifferentiation and responsible for primary and secondary growth respectively.

Edmentum confirmed.

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.    

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.