ANATOMY

Detailed explanation-1: -Answer and Explanation: The diameter of the blood vessels most directly affects blood flow resistance. Increased vessel diameter means lesser contact of blood with the vessel walls, thus decreasing the resistance and increasing blood flow velocity.

Detailed explanation-2: -In blood vessels, most of the resistance is due to vessel diameter. As vessel diameter decreases, the resistance increases and blood flow decreases. Very little pressure remains by the time blood leaves the capillaries and enters the venules.

Detailed explanation-3: -Answer and Explanation: Of the listed possibilities the one that would increase the rate of flow in blood vessels is decreasing the length and increasing the diameter of the blood vessels.

Detailed explanation-4: -increased pressure of the blood entering the vessel. The blood pressure for the blood flow is created by the hydrostatic pressure of the blood vessels that helps to move the blood from the area of higher to lower pressure. The increase in blood pressure increases the flow of blood through a blood vessel.