A mechanical wave is created when a source of energy causes .
A. a vibration to travel through a medium
B. a displacement that must be filled
C. the structure of a medium to be altered

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

the pseudoscience are like beliefs, theories, or like practices that are considered scientific