Observation

Not many candidates attempted this question and most of those who attempted it performed poorly. The characteristics of stack include:
- an erosional feature
- found off  the coast
- a pillar of hard resistant rock
- stands in water away from the coast
- varies in size depending on the resistance of the headland rock
- size continues to reduce
- further erosion of the stack produces another feature called stump
- examples include the Old Man of Hoy in the Orkneys; the Elephant Rock in the coast of Oregon in USA; the Needles in Isles of Wight; Old Harry Rocks in the Isles of Purbeck; Coast of Dakar; Coast of Ghana between Takoradi and Secordi; Coast of Scotland.

Formation of stack goes thus:
-           formed along the coast
-           formed by wave erosion
-           a headland is needed  for a stack to be formed
-           wave erosion attacks both sides of the headland
-           two caves are formed at both sides of the  headland
-           further wave abrasion and hydraulic action deepen the caves
-           further erosion of the caves produces an arch when the two caves join together
-           the roof of the arch collapses
-           the seaward portion of the headland  remains as a pillar called stack
Characteristics of sand bar are:
-           a coastal landform
-           made up of sand and shingles
-           a wave depositional feature
-           lies a few metres above sea level
-           found in indented coasts and mouth of rivers
-           lies parallel to the shore
-           could be up to 20 – 26km in length
-           could be covered and exposed at low tide
-           could be a bay, bar or an offshore bar
-           called tombolo if it joins two land masses
-           examples are Escravos and Forcados bars (Nigeria), Senya Beraku near Winneba (Ghana), Lumley Beach (Sierra Leone), Chesil Beach in Dorset (England).
Mode of formation of sand bar goes thus:
-           formed near the coast
-           formed by wave deposition
-           takes place in shallow sea waters
-           sea waves push sand towards the shore
-           the backwash and under currents drag materials down the beach
-           rivers bring alluvium toward the shore
-           further deposition under the water builds up the bar
-           coasts should be sheltered from strong currents to allow accumulation of deposits
-           bars grow or extend in the direction of long shore drift