Question

4. The red color of rocks and soil containing iron-rich minerals is caused by

abrasion
chemical weathering
mechanical weathering
erosion
5. The erosive ability of a river is affected by all of the following except:

stream gradient
stream temperature
stream load
stream discharge
6. A river system begins to form in a given area when

precipitation exceeds evapotranspiration
precipitation exceeds condensation
evaporation exceeds precipitation
condensation exceeds precipitation