Explanation:
Waterfalls often form in the upper stages of a river where it flows over different bands of rock. It erodes soft rock more quickly than hard rock and this may lead to the creation of a waterfall. The soft rock erodes more quickly, undercutting the hard rock.
Answer:
smaller political units maintaining their sovereignty
Explanation:
Confederation is the name given to a country that is a federation, but the states that make up that country maintain their sovereignty, separate from the power of the federal government. In this case, to maintain a confederation it is essential that the smaller political units, the states, maintain their sovereignty. This is different from a federation, because in a federation, states lose sovereignty, transferring it to the federal government.