Final answer:
Fly strips are not useful in eliminating insect breeding places as they only capture existing adult insects, not addressing the breeding sites. Therefore, the correct option is d.
Step-by-step explanation:
The item that is not useful in eliminating insect breeding places from the options provided is D. Fly strips. Fly strips are a method used to capture existing adult insects, particularly flies, but they do not address or eliminate the breeding sites where insects multiply. On the other hand, tightly covered garbage cans, prompt disposal of garbage, and the elimination of pools of water all serve to remove or reduce areas where insects, such as mosquitoes and flies, might breed. Eliminating potential breeding sites is a crucial aspect of vector control and prevents the proliferation of pests that can carry diseases.