To deny pests access to the building, what is a correct control at exterior openings?

解析

Denying pests access means the outer openings are protected: exterior doors self-closing and tight-fitting, open windows screened, and gaps around utility lines and pipes sealed. A wedged-open delivery door, an unscreened window, and a two-inch gap under a door are all open invitations, and a mouse can pass through a gap far smaller than two inches. Exclusion at the building envelope is the first line of an effective pest program, ahead of any pesticide.