Slope development over time and the concept of slope retreat

Question 1

explain slope decline/down wasting:

Answer 1

this theory proposed by W. M. Davis states that slopes that develop in humid climates are initially eroded vertically causing uplifted land masses.

over time the continous water washing down slope will cause convex upper slope to subcome and eventually land will be almost flat this is called a peneplain.

Question 2

explain slope replacement:

Answer 2

the steeper part becomes more gentler as more scree or taulus moves to the base of slope

Question 3

explain slope retreat:

Answer 3

This theory, formulated by a South African, L. C. King states that, when initially rivers erode into an uplifting landmass with time the crest, scarp and taulus maintain their gradient but are shifted backwards making the pediment longer and longer increasing shape of concavity. the pediment becomes a pediplain.

this theory is based on an idea of scarp recession or parallel retreat.