teh type of erosion mainly found on the upper course of rivers are:
a.hydralic action,lateral and
abrasion
b.hydralic action and solution
c.abrasion and solution
d.hydralic action and attrition
To determine the type of erosion mainly found on the upper course of rivers, you can analyze the given options and identify which processes are associated with this particular stage of a river's journey. Here's a breakdown of the options:
a. Hydraulic action, lateral erosion, and abrasion: Hydraulic action refers to the forceful action of moving water dislodging and transporting sediment. Lateral erosion occurs when a river erodes the riverbanks sideways, widening the channel. Abrasion involves the river's load (e.g., rocks and sediment) wearing away the riverbanks and bed. All three processes mentioned in option a contribute to erosion but are not specific to the upper course.
b. Hydraulic action and solution: Hydraulic action (as explained above) is the forceful action of water on the river channel, and solution occurs when water dissolves certain types of rocks or minerals. While these processes do take place in rivers, they are not the main types of erosion in the upper course.
c. Abrasion and solution: Abrasion (as explained previously) is the process of material carried by the river causing erosion through friction, while solution refers to the dissolving of certain rocks or minerals by water. Both of these processes are known to occur in the upper course of rivers, contributing to erosion.
d. Hydraulic action and attrition: Hydraulic action (as explained before) is the forceful action of flowing water, and attrition involves the wearing down of particles carried by the river crashing into each other and becoming smaller and more rounded. Both of these processes are known to occur in the upper course of rivers, contributing to erosion.
Based on the above analysis, the correct answer would be option d: hydraulic action and attrition.