<span>The genetic term used to describe an observable trait is phenotype. More specifically phenotype is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.</span>
Destruction of myelin will affect the nerve and there will be the less conduction of electrical impulses from the brain to other parts of the body and the nerve signal sent to the brain are delayed. These damaged nerve areas form sclerosis which disrupts the signalling capacity of the nerve. This may occur due to genetic defects, infectious agents, auto immune reactions and trauma.
It shows the evolution of an being. "Fossil record, history of life as documented by fossils, the remains or imprints of the organisms from earlier geological periods preserved in sedimentary rock." from https://www.britannica.com/science/fossil-record
The answer is, "B", "Developing country".
