The neurons function such that the form an intricate circuitry which is directly or indirectly has influence on brain tissues and other cellular components. The neuronal circuitry is affected by brain injury causing the death of glial cells and neurons and the connection is destroyed between them.
Brain injury mainly results from trauma or strokes and the components that are damaged include neurons, glial cells like microglia, astrocytes and oligodendrocytes, the blood vessels and cells producing and recycling the cerebrospinal fluid or CSF that lines up the ventricles in brain. The blood flow is disrupted and the blood-brain barrier is also affected. The production, distribution and the re-absorption of the cerebrospinal fluid brings about changes in the metabolism and functioning of the cells in proximity of the dying tissues and also in remote brain regions which are connected anatomically to the injured area.
The best answer to the question that is being presented above would be letter a. The poplar trees used by the company and its factories which are genetically engineered would be used for phytoremediation. They use poplar trees to replenish the nutrients lost around the factories.