Answer:
Demography
Explanation:
Because of population the land is getting low
<span>Much of the commercially important waterways of the United States consist of the Mississippi River System—the Mississippi River and connecting waterways. .... States on the Gulf Coast and throughout the Midwest and Ohio Valley ...</span>
If you could dig a tunnel right through the Earth you could theoretically free-fall to the centre of our planet in just eighteen minutes. You can’t, of course: such a tunnel would have to tolerate temperatures as high as the surface of the Sun and pressures three and a half million times greater than those at the Earth’s surface.
What is there any options ? <span>
</span>
