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i) Other than seif dunes, name two other types of sand dunes
ii) Give five characteristics of seif dunes
iii) State four factors that facilitate the formation of the sand dunes

Answer Text:
i) - Barchans
- Transverse / wake dunes
ii) - They lie parallel to each other
- They rise up to 100m/high and their length can exceed 100km/long
- They lie parallel to the direction of the prevailing wind
- They have a sharp knife like crest
iii) - Availability of sand
- Strong winds blowing in one direction for a long time
- Presence of obstacles e.g. rocks or vegetation
- Occasional rainfall hardening the ground causing deposition
- Presence of ground water reaching the surface
- Human activities like mining, heaping materials on the surface that acts as anchors for sand deposits