A feature produced by water in desert areas is-------

Step 1: Analyze the question The question asks for a desert feature produced by water (not wind). So we must separate wind-formed features from water-formed ones.

Step 2: Explain each option

• A. Barchans are crescent-shaped sand dunes formed by wind deposition. Not water.
• B. Zeugens are tabular ridges of resistant rock capped over softer rock, formed by wind abrasion (differential erosion). Not water.
• C. Yardangs are streamlined, sharp-crested ridges that run parallel to the prevailing wind, formed by wind abrasion. Not water.
• D. Wadis are dry river valleys or channels in deserts. They are carved by flash floods and running water after occasional heavy rainfall. This is a water-formed feature.

Step 3: Conclusion Only wadis are produced by water action. The others (barchans, zeugens, yardangs) are all wind features.

Correct answer: D. Wadis

Exam tip: Remember this grouping:

• Wind features: barchans, seif dunes, zeugens, yardangs, deflation hollows, mushroom rocks (pedestal rocks).
• Water features in deserts: wadis, playas, pediments, bajadas, alluvial fans, inselbergs (partly).

When you see "water" and "desert" together, think wadi first (Arabic for "valley").