Cells are living and what cells produce is not living.Plasma is a mixture of 92% water and many substances dissolved in it which are in the process of transport.Like,glucose,aminoacids,vitamins hormones etc.The cells present in the plasma are living(RBCs,WBCs) which are moving along with flowing plasma.Plsama just gives a flowing medium to blood.With so much water and substances dissolved in it it is non living and it is intercellular substance as it is present between the cells of the blood.