What does it have in it meaning in mother to son poem

What is the best way to manage oil transport on waterways? a. prevent oil spills and regulate the amount of oil that can be shipped at one time.b. use a skimmer, containment boom or chemical dispersant to clean up spilled oil.c. burn off oil spills from the water's surface when they occur.

What is implied in this sentence from mark twain's "the ? 1,000,000 bank-note"? i was puzzled, and wanted to discuss the matter a little further, but they didn't; so i took my leave, feeling hurt and insulted to be made the butt of what was apparently some kind of a practical joke, and yet obliged to put up with it, not being in circumstances to resent affronts from rich and strong folk.

Which type of map best shows differences in elevation?