Question

In an arid environment, winds of similar intensity blow in nearly opposite directions in alternate seasons. Which dune type is most likely to form in such an environment?

• A. Barkhan
• B. Transverse dunes
• C. Seif
• D. Lunate

Hint:

Seif dunes form in arid environments with alternating wind directions, creating long, narrow ridges aligned with the wind.

Answer 1

The Correct Option is C

Step 1: Read the wind pattern.
The winds here are about equal in strength but blow nearly opposite ways in different seasons. So no single direction wins.

Step 2: What shape this builds.
Two opposing winds of similar force pile sand into long, sharp ridges that line up with the wind path. These are seif dunes.

Step 3: Rule out one way wind dunes.
Barkhan and transverse dunes both need a steady wind from one side, and lunate dunes are crescents from one wind too. They do not match a two way wind.

Step 4: Confirm seif.
Seif dunes are the classic long linear dunes formed when seasonal winds reverse. That fits the question exactly.

Step 5: Final choice.
So the dune type is the seif.
\[ \boxed{\text{Seif}} \]