Identify each of the following mixtures as either homogeneous or heterogeneous and as a solution, a suspension, or a colloid. blood homogeneous heterogeneous solution colloid suspension salad dressing homogeneous heterogeneous solution colloid suspension

With reference to the solutions, following things may be noted
1) Homogeneous solutions comprises of single phase.
2) Heterogeneous solution comprises of more than one phase.
3) in colloidal solution, solute is evenly distributed in solvent. in such system, it is difficult to separate solute and solvent.
4) in suspension, there is an uneven distribution of solute in solvent. In such system, solute and solvent gets separated on standing long.  

Blood is a homogeneous and colloidal solution,
Salad dressing is a heterogeneous and suspension solution.