The Black Death was an epidemic of bubonic plague, a disease caused by the bacterium Yersinia pestis that circulates among wild rodents where they live in great numbers and density. Such an area is called a âplague focusâ or a âplague reservoirâ.
Diffusion is the net movement of molecules or atoms from a region of high concentration to a region of low concentration.his is also referred to as the movement of a substance down a concentration gradient. A gradient is the change in the value of a quantity (e.g., concentration, pressure, temperature) with the change in another variable (usually distance).
Answer Wiki. No, diffusion is a spontaneous mechanism and doesn't require energy. Diffusion: Movement of particles from high concentration regions to low concentration. The fundamental reason of why diffusion takes place can be attributed to the random kinetic motion of molecules. The random motion of these molecules is just because of the energy they possess.