Why
is the hepatic portal
portal vein
unique ?​

Blood flow to the liver is unique in that it receives both oxygenated and (partially) deoxygenated blood. As a result, the partial gas pressure of oxygen (pO2) and perfusion pressure of portal blood are lower than in other organs of the body.

vascular tissue transports materials from the environment into the plant.

answer; i believe the correct answer is ( proteins );