Final answer:
A sand dune that is crescent-shaped with horns pointing in the wind direction is called a barchan. Barchans are typical in deserts with limited sand and consistent wind patterns, and similar processes form dunes on Mars and Earth.
Step-by-step explanation:
The type of sand dune that is shaped like a crescent and has horns pointing toward the direction the wind blows is called a barchan. Barchans are a common dune type found in sandy deserts, and they form under conditions where there is a limited supply of sand and a relatively unidirectional wind. Unlike dunes on Earth, the Martian landscape also features dunes, signaling the presence of strong wind activity and the capability of Mars' atmosphere to move sand and form such structures. Although the Martian environment is different, the erosional and depositional processes that create dunes are conceptually similar to those on Earth.