Final answer:
The federal mineral-resource laws of the late nineteenth century were designed to preserve mineral resources by restricting exploitation in key industries such as transportation, steel production, and oil and gas exploration and refining.
Step-by-step explanation:
The federal mineral-resource laws of the late nineteenth century were indeed designed to preserve mineral resources by restricting exploitation. These laws were part of the government's efforts to regulate monopolies and key industries, including transportation, steel production, and oil and gas exploration and refining. The purpose was to prevent the overexploitation and depletion of mineral resources.