When a drawing of a circle made in the center of a piece of paper with a black marker gets wet, the marker bleeds, and as the water moves through the paper the ink separates into several colors. What method of separation does this describe?
evaporation
distillation
filtration
chromatography

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost