Final answer:
Capillary pressure is the force required to occlude the smallest circulatory vessels. It is responsible for driving fluid out of the capillaries and into the tissues.
Step-by-step explanation:
The force required to occlude the smallest circulatory vessels is called Capillary pressure. Capillary pressure is the pressure exerted by blood against the wall of a capillary and is responsible for driving fluid out of the capillaries and into the tissues. It is one of the primary forces driving fluid transport between the capillaries and tissues.