Tissues are able to autoregulate their rate of blood flow by controlling a. arterial blood pressure. b. perfusion pressure. c. venous return to the heart. d. vascular resistance.

Vascular resistance

Explanation:

Vascular resistance can be defined as the resistance in the blood vessels which should be overcome to allow blood flow through the circulatory system.

When the blood vessel dilate then blood flow increases due to decrease in the vascular resistance.

In case of vasoconstriction the vascular resistance increases and the blood flow decreases due to this resistance.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).