One of the first things that most designers forget about CSS descendant selectors is that they are flexible. When CSS defines a descendant, it doesn't care whether the tag in question is the direct child, the grandchild, or some great-great-great-descendant of the initial element.
From the retina, visual information passes onto the bipolar cells and then to the optic nerve's ganglion cells. The optic nerve, which begins at the retina, is the sole visual pathway to the brain. Light information is conveyed as an electrical action potential through the neurons.
The axon is a key component of nerve cells over which information is transmitted from one part of the neuron (e.g., the cell body) to the terminal regions of the neuron. Axons can be rather long extending up to a meter or so in some human sensory and motor nerve cells.