what are 5 examples of mixtures?
['Smoke and fog (Smog)', 'Dirt and water (Mud)', 'Sand, water and gravel (Cement)', 'Water and salt (Sea water)', 'Potassium nitrate, sulfur, and carbon (Gunpowder)', 'Oxygen and water (Sea foam)', 'Petroleum, hydrocarbons, and fuel additives (Gasoline)']