Where a river flows from an area of harder rock to an area of softer rock, the softer rock may weary away, forming a drop called a(n)

The correct answer is:

b. meanders.

Explanation:

A meander, in overall, is a curve in a sinuous stream or river. Meander forms when leaving water in a stream disintegrates the outer banks and widens its valley and the central part of the river has less power and hastens silt. It is produced by a stream or river turning from side to side as it runs across its floodplain or changes its channel within a valley. A meander is created by a stream or river as it consumes the grounds comprising an outer, concave bank (cut bank) and deposits this and combined sediment downstream on an inner, convex bank which is typically a point bar.

answer; polycythemia is the correct answer;