Final answer:
True, trench boxes and shoring both serve to protect workers from cave-ins. High-voltage wires are not wrapped in insulating material but are held by insulating connectors. Prairie dog burrows provide shelter for other species and protect from predators, but can inhibit plant growth above ground.
Step-by-step explanation:
Both trench boxes and shoring are indeed used to protect workers from cave-ins during excavation work, making the statement true.
Trench boxes, also known as trench shields, are structures that are placed in the excavated area to prevent the walls from collapsing. Shoring, on the other hand, involves propping up the walls of the trench with supports to prevent soil movement and potential cave-ins.
Regarding the high-voltage wires, the statement is false. While these wires are held aloft by insulating connectors to prevent the current from grounding, they are typically not wrapped in insulating material. This is because the air acts as an insulator and the high elevation of the wires keeps them well away from objects that could conduct electricity to ground.
The burrows prairie dogs dig do indeed serve the ecosystem by providing shelter for other species and protection from predators. However, they can also lead to a reduction in the growth of plants above ground due to soil disruption and grazing.