Winds blowing constantly in one direction in rocky deserts tend to form which of the following landforms?

Introduction / Context:
Desert landforms are classic examples of how wind acts as an agent of erosion and deposition. In rocky deserts, where bedrock and consolidated sediments are exposed, persistent winds blowing from a dominant direction gradually sculpt distinctive shapes. This question asks which specific landform is produced by winds blowing constantly in one direction in such rocky deserts, an important concept in geomorphology and physical geography.

Given Data / Assumptions:

• The setting is a rocky desert, not a sandy dune field or a river valley.
• Winds are described as blowing constantly in one direction over a long period.
• The options include chimney like pillars, mushroom rocks, yardangs, demoiselles, and sand dunes.
• We must match the process of unidirectional wind abrasion with the correct landform name.

Concept / Approach:
Yardangs are streamlined ridges of rock carved out by wind erosion in arid environments, especially where strong winds blow dominantly from one direction. The wind removes softer material and smooths the slopes that face into the wind and on the lee side, so the ridges become elongated parallel to the prevailing wind. Mushroom rocks form by wind abrasion near the base of an isolated rock, producing a narrow pedestal, but they are not necessarily aligned as long ridges. Chimney like pillars and demoiselles are more associated with differential erosion by water and other processes, while sand dunes are mainly depositional features built by moving sand, not by uniform abrasion of bedrock ridges.

Step-by-Step Solution:
Step 1: Focus on the phrase winds blowing constantly in one direction, which implies repeated abrasion along a specific orientation. Step 2: Recall that yardangs are elongated ridges sculpted in soft rock or sediment, oriented parallel to prevailing winds in deserts. Step 3: Recognise that mushroom rocks are isolated features with a narrow base and broader top formed by sand blasting near ground level, not long parallel ridges. Step 4: Chimney like pillars and demoiselles are more related to differential erosion with limited reference to wind direction, and they do not typically appear as systematic aligned ridges. Step 5: Sand dunes are accumulations of loose sand, which can migrate with wind, but the question emphasises rocky deserts and erosional sculpting rather than deposition of sand.

Verification / Alternative check:
Most physical geography textbooks describe yardangs as narrow, elongated ridges separated by wind eroded troughs, commonly found in deserts like those of Central Asia, Egypt, and western China. Illustrations often show them oriented parallel to the main wind direction. Mushroom rocks, chimney rocks, and demoiselles are given as other examples of wind or water shaped features, but the one that clearly matches the condition of unidirectional wind over rocky surfaces is the yardang landform.

Why Other Options Are Wrong:

• Tall chimney like rock pillars: These are more characteristic of differential erosion by weathering and water and do not necessarily align with wind direction.
• Mushroom rocks with narrow bases: Formed by wind abrasion near the ground, but they are isolated features and do not reflect persistent directional alignment over large areas.
• Demoiselles formed mainly by river erosion: These are erosional remnants left by fluvial processes, not by dominant wind erosion in rocky deserts.
• Sand dunes built by shifting sand: Primarily depositional landforms created from loose sand, not streamlined ridges carved in bedrock by abrasion.

Common Pitfalls:
A common error is to choose mushroom rocks, since they are a well known desert landform created by wind. However, the question emphasises winds blowing constantly in one direction in rocky deserts, which is characteristic of yardangs that develop as long ridges aligned with the wind. Another pitfall is to confuse depositional dunes with erosional landforms like yardangs. Remembering whether the process is mainly erosion of bedrock or deposition of loose sand is key to answering correctly.

Final Answer:
Winds blowing constantly in one direction in rocky deserts most commonly form yardangs, long ridges aligned with the wind.