application or intradermal injection of a substance to the skin to test the body's reaction to it. Such a test detects an animal's sensitivity to such allergens as dust and pollen, or to preparations of microorganisms believed to be the cause of a disorder.
A direct relationship graph is a graph where one variable either increases or decreases along with the other. The general equation for a direct relationship graph is y = mx + b, where y denotes the...
This is called a direct relationship. (In an equation such as Y = -X, the relationship is still direct, although Y decreases as X increases, because X1/X2 = Y1/Y2) One way to picture this relationship that doesn't involve any math is to think about a seesaw or teeter-totter that is in balance with one child on each end.