Learning and remembering are closely related features. I believe
that illustrations are the most comprehensive and concise ways
for accessing the brain to enhance learning and remembering.
Thereupon, in my book I preferred to explain many subjects by
diagrams. On the other hand, if the subject of concern is a human
being, the task of explaining becomes even harder, since the
human being has a very complex system of anatomy, physiology,
biochemistry, histology and biophysics.