A rejuvenated topography is characterized by:
A. Knick Point
B. Incised Meanders
C. Valley in Valley
D. Structural Benches

Question

A rejuvenated topography is characterized by: 
A. Knick Point 
B. Incised Meanders 
C. Valley in Valley 
D. Structural Benches

Accepted Answer

Option 3 is the correct answer because a rejuvenated topography is characterized by Knick Points, Incised Meanders, and Valley in Valley features. Here's why:

*   **Knick Point:** Rejuvenation, often caused by a drop in base level (e.g., sea level fall or tectonic uplift), increases the erosive power of a river. This increased erosion creates a sharp break in the river's longitudinal profile, known as a knick point. The knick point migrates upstream as the river cuts down to establish a new equilibrium profile.

*   **Incised Meanders:** When a meandering river experiences rejuvenation, it begins to erode vertically into its existing floodplain. This results in the formation of incised meanders, where the river channel is deeply entrenched within its former meander pattern. The meanders retain their original sinuous shape but are now confined within steep valley walls.

*   **Valley in Valley:** Rejuvenation can lead to the formation of a smaller valley within a larger, older valley. The river, with its renewed erosive power, cuts a new, deeper valley into the floor of the pre-existing valley. This creates a distinct "valley in valley" morphology, indicating multiple stages of erosion and uplift.

Now, let's explain why the other options are incorrect:

*   **Option 1 (A, B, C and D):** While Knick Points, Incised Meanders, and Valley in Valley are characteristic of rejuvenated topography, Structural Benches are not necessarily directly related to rejuvenation. Structural benches are formed due to differential erosion of alternating layers of resistant and less resistant rock. While rejuvenation *could* enhance the visibility of existing structural benches, they are not a *defining* characteristic of a rejuvenated landscape in the same way as the other three.

*   **Option 2 (A, B and D):** As explained above, Structural Benches are not a primary indicator of rejuvenation. The "Valley in Valley" feature is a more direct and common consequence of rejuvenation than structural benches.

*   **Option 4 (A and B):** While Knick Points and Incised Meanders are strong indicators of rejuvenation, the absence of "Valley in Valley" makes this option less complete. The "Valley in Valley" feature provides further evidence of multiple erosional cycles driven by rejuvenation. Therefore, including it strengthens the description of a rejuvenated topography.

In conclusion, Option 3 (A, B, and C) is the most accurate and comprehensive answer because it includes all the key features that directly and consistently result from the process of topographic rejuvenation.