<span>Stimulation of thoracic or lumbar spinal regions; impulse reaches chain ganglion; acetylcholine release</span>. Acetylcholine is released if the synapse happens in the sympathetic ganglion, if the synapse is in post-ganglionic neuron, norepinephrine is released.
There numerous of them but some of them would be contaminated soil which can be followed with altered soil chemistry that contains fewer soil organisms that are essential. The third one would be surface runoff due to extensively modified hydrology of the area.
The correct answer would be letter C.