Imagine that you have four food dyes to test, A, B, C and D. Imagine that you going to investigate which food dye diffuses most quickly.
a. which variable will you change?
b. which variable will you measure? how will you do this?

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary