1. What organisms keeps the ecosystem going but you can't see them with the naked eye?

The answer is bacteria (microorganisms)

Explanation:

Bacteria can't be seen with the naked eye but it's part of a species that make up the biodiversity.

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

im not exactly sure but i think its b!