Final answer:
Albumin is the plasma protein mainly responsible for establishing colloid osmotic pressure in blood vessels and draws water from the tissues, maintaining blood volume and pressure.
Step-by-step explanation:
The plasma protein mainly responsible for establishing colloid osmotic pressure in blood vessels is albumin.
Albumin is the most abundant plasma protein and contributes significantly to the osmotic pressure of blood.
Its presence holds water inside the blood vessels and draws water from the tissues, maintaining blood volume and pressure.