Final answer:
The main protein in blood plasma is albumin. It is the most abundant plasma protein, synthesized in the liver, and performs important functions like transporting hormones and fatty acids.
Step-by-step explanation:
The main protein in blood plasma is albumin. Albumin is the most abundant plasma protein, accounting for most of the osmotic pressure of plasma. It is synthesized in the liver and functions as a binding protein, transporting hormones and fatty acids, buffering pH, and maintaining osmotic pressures.