HeLppP asap I’ll mark you as brainlister

It's A

Explanation:

It starts as one molecule and splits into two which is the definition of a decomposition reaction

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