Albumin is important factor in maintaining osmotic pressure, has:

Ans. is 'a' i.e. low molecular weight and high blood concentration First lets make it clear that - Osmotic pressure is determined by the number of particles in solution and not by the mass of the particle.Thus more the number of particles, in solution more its contribution of osmotic pressure.Its also obvious that 1 gm of a heavy molecular weight protein will contain a lesser number of particles than 1 gm of a low molecular weight protein. So 1 gm of a low molecular weight protein will exert a higher osmotic pressure.* Of the three major types of plasma proteins albumin has the highest concentration (about 66%) and the lowest molecular weight Therefore it has the maximum number of molecular in the plasma and contributes maximally to osmotic pressure (80%).Plasma ProteinsMWConcentrationContribution to plasma osmolality* Albumin69,0003.5-5 gm%80%* Globulin1,40,0002.0 gm%20%* Fibrinogen4,00,0000.3 gm%0%