What is a burn that affects only the top layer of skin?

a.
first-degree burn

b.
second-degree burn

c.
third-degree burn

Which is one way that sinkholes can form? a) tornadoes touch down and destroy trees and brush b) rivera overflow during a storm and wash away nearby land c) rainwater flows away from a depression in the ground d) groundwater dissolves the limestone and other rocks in the ground