Final answer:
Underground installations require special permits, may contain utility lines, and may be marked with color codes, but are not always visible on the surface.
Step-by-step explanation:
The statement that is not true about underground installations is that they are always visible on the surface. Underground installations, such as utility lines and pipelines, do require special permits before construction or placement due to their impact on the surrounding environment and the budgeting constraints of the project. Indeed, underground installations often contain various utility lines including those for electricity, water, gas, and telecommunications. To prevent accidental damage, these lines may be indicated above ground by a system of color codes, which informs workers or the general public about the type of utility buried underneath.
Regarding the use of materials and natural resources, underground installations often use durable materials resistant to environmental conditions, such as PVC, concrete, and steel. Additionally, by placing food reserves underground, some organisms are taking advantage of favorable soil conditions as the moisture and temperature are less variable, making such reserves more nutritious and abundant away from the prying eyes of potential predators.
Overall, the key to safe and effective underground installations lies in proper planning, adherence to regulations, and clear marking systems, among other considerations.