Albumin is a protein found in blood plasma (the ground substance in blood), but it doesn’t cross the cell membrane of a red blood cell. Imagine that we have a test tube containing only water and albumin. When we place red blood cells in the test tube, the cells shrink. Before we placed the red blood cells into the tubes, the osmolarity of the fluid must have been than the inside of the red blood cell. a. Higher than b. Lower than c. Equal to d. Any of the above could be true.