Final answer:
To make rodent signs more visible in storage areas, you can paint a white line on the floor 15 cm (6 in) from the wall. Another option is to use a blue light bulb and dust the area to highlight rodent urine or droppings. Raising the humidity level or leaving the floor wet would not help in making rodent signs more visible.
Step-by-step explanation:
To make rodent signs more visible in storage areas, you can paint a white line on the floor 15 cm (6 in) from the wall. This serves as a visual barrier and can help detect any movement or droppings near the wall. The contrast between the white line and the surrounding area makes it easier to spot any signs of rodent activity.
Raising the humidity level or leaving the floor wet would not necessarily make rodent signs more visible. In fact, this could create potential hazards such as mold or slippery surfaces. Lastly, using a blue light bulb and dusting the area can help highlight rodent urine or droppings, as they may appear fluorescent under certain types of light.