A high viscosity of blood causes an increased resistance in the blood vessels and leads to slow blood flow.
Viscosity refers to the thickness of blood. This thickness is caused by the number of red blood cells. Thick blood travels through blood vessels at a slower rate than thin blood.
All living things are made up of cells. Cells are the basic units of structure, function and physiology in living things. Living cells can come only from other pre-existing cells. Hope this helps!