Question 1685 Deck Safety

The correct answer is D) stop insects from entering. Screens on the vents of potable water tanks are primarily used to prevent insects, such as mosquitoes or flies, from entering the tank and potentially contaminating the drinking water. This is a critical sanitation measure to maintain the quality and purity of the water supply. The other answer choices are not directly relevant to the purpose of the screens on potable water tank vents. Preventing explosions (A), backups (B), or filtering the incoming air (C) are not the main reasons for having screens on these vents. The screens serve to keep out unwanted pests and debris, ensuring the water remains safe for human consumption.