Final answer:
The landform not found in the eastern United States is deserts. The Eastern U.S. features mountains, plains, and plateaus, but not deserts, which are typical in the southwestern U.S.
Step-by-step explanation:
The landform not found in the eastern United States is c) Deserts. The eastern United States is home to a diverse range of landforms, which include mountains, such as the Appalachian Mountains, plains like the Coastal Plain that stretches from New York to Texas, and plateaus like the Piedmont. However, deserts, which are typically characterized by extremely low precipitation and sparse vegetation, are not a feature of the Eastern U.S. landscape. In contrast, deserts are more commonly associated with the southwestern part of the country, in states such as Arizona and New Mexico.Moreover, the eastern United States is characterized by a humid subtropical climate in the south and a humid continental climate in the north, both of which support rich vegetation and diverse ecosystems not conducive to desert formation. This main answer explains the absence of deserts in the eastern region of the U.S. while highlighting the existence of other landforms like mountains, plains, and plateaus.