Which of the following is a key function of systemic pesticides?

Systemic pesticides are designed to be absorbed by plants and then translocated throughout their tissues. This characteristic allows the pesticide to protect the entire plant from pests, as it becomes part of the plant's circulatory system. When insects feed on the plant, they ingest the systemically active pesticide, leading to effective pest control.

The other options do not accurately represent the primary function of systemic pesticides. Surface control typically involves contact pesticides that act on the outer surfaces of plants. Eliminating pests quickly can be a feature of certain pesticides, but it does not specifically highlight the systemic action of being absorbed and circulated within the plant. Affecting the growth of soil organisms is more associated with certain types of pesticides that may impact non-target organisms rather than the defined systemic action of targeting pest insects through uptake.