Which of these is true about pure substances? They can only contain one type of molecule. They may contain one type of atom or one type of molecule. They can only contain one type of atom. They can contain different types of atoms and molecules.

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

can you list the answers so i can answer