IL. MULTIPLE CHOICE. Choose the one alternative that best completes the statemen
ID: 294193 • Letter: I
Question
IL. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. (2pts each) 1) The longitudinal profile of a stream at equilibrium is A) a smooth curve B) steepest in the beadwaters C) nearly flat where it enters the sea. D) concave upward. E) all of the above 2) The lowest level to which a stream can erode its channel is called the stream A) gradient B) base level C) capacity D) competence. E) degradation. 3) A stream transports its sediment load B) in solution. C) by traction. D) by suspension and solution. E) all of the above 4) Which of the following is the dominant landform on continents? A) mountains B) plains C) stream valleys D) plateaus E) deserts 5) A stream abrades or erodes its channel mainly by means of A) bank deposits. B) the fragments it carries. C) rapidly moving water. D) base level. E) material in solution. 6) Saltation refers to A) the rate at which dissolved salts reach the ocean. B) the abrasion and traction of particles C) the jumping or bouncing of particles along a stream bed. D) transport of large boulders. E) the rolling of pebbles along a stream bed.Explanation / Answer
1. Longitudinal profile of a stream at equilibrium is a smooth curve, steepest in the headwaters, nearly flat as it enters the sea and concaves upward. This is because of a balance between sediment load, velocity, slope, and volume of the stream are in balance. Thus, the correct option is E).
2. Stream gradient is defined as the change in height per unit distance. Stream capacity is the total sediment load a river can hold and transport. Stream competence is the amount of largest sediments that a river can transport. Stream degradation is a process due to which stream gradient becomes gentle. The base level is the lowest level up to which a stream can flow and erode its channel. Thus, the correct option is B).
3. Solids, i.e. sediment load, can be transported in streams through traction or rolling, suspension, solution. Thus, E) is the correct option.
4. Mountains are the most dominant landform on continents as they are the tallest and steepest of all the landforms. Plains, valleys, plateaus, and deserts are relatively low-lying and eroded. Thus, option A) is correct.
5. Stream erodes its banks and bed, i.e. its channel, mainly through the rapid flow of water. No other option defines an agent which are directly responsible for eroding a stream channel. Thus, option C) is correct.
6. Saltation refers to the transportation of particles through bounces and jumps. Since none of the other options define the process of saltation, the correct option is C).