Which substances play an important role in communication between cells in a multicellular organism by acting as chemical messengers?

Hormones

Explanation:

Hormones are chemical messengers released in one part of the body as chemical messengers into the bloodstream to achieve target results in another part of the body. The endocrine system is responsible for regulation of the internal environment (homeostasis).

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