Blood contains nacl, protein, and cells. the nacl is in a(n) the protein is in a(n) and the cells are in a

The answers are solution, colloid, and suspension respectively. 

NaCl or salt is dissolved in the blood. So this makes blood and salts a solution. You won't be able to discern the NaCl in a solution of blood and NaCl.

Proteins in the plasma make blood a colloid. Protein particles are bigger than particles in a solution but are smaller than particles in a suspension. 

Lastly, blood cells and blood make up a suspension. You would notice this characteristic in blood because red blood cells settle. 

You can observe this when your blood is drawn. When it is placed in a test tube and left alone or placed in a centrifuge. The components separate into liquid on top, where you cannot see particles like salt; plasma in the middle, which has pale yellow color and also contains proteins; and the red blood cells at the bottom that settled.