Final answer:
The plant life is unable to grow on the shores of Lake Powell due to constantly changing water levels.
Step-by-step explanation:
The correct answer is B. Because the water levels are constantly changing. Lake Powell is a man-made reservoir that experiences fluctuating water levels due to human interventions such as water withdrawals and dam operations. These changing water levels prevent stable conditions for plant life to establish and grow on the shores. The constant disturbances and submergence of the shoreline limit the availability of necessary resources for plant growth, leading to the inability of plant life to thrive in this environment.
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