Final answer:
The cross section that best represents the settling pattern of quartz particles of various sizes in calm water is the one with larger particles settling at the bottom and smaller particles on top, as sedimentation principles and graded bedding indicate larger, heavier particles settle first.
Step-by-step explanation:
In analyzing the settling pattern of quartz particles of various sizes in deep, calm water, it is important to consider the physical principles governing sedimentation and particle size dynamics in a fluid medium. The process of sedimentation involves particles settling to the bottom of the water body due to their weight. This phenomenon is influenced by factors such as particle size, density, and the viscosity of the fluid.
Graded bedding is a relevant concept here; it's a geological structure where a sedimentary layer indicates a gradation in particle size, with coarser material at the bottom and finer material toward the top. This gradation reflects a decreasing transport energy over time. Similar principles apply to particles settling in water. Larger, heavier particles settle faster than smaller, lighter particles due to greater gravitation force acting on them and less resistance to sinking. Therefore, they tend to reach the bottom of the water body first.
Given this understanding, the correct answer to the student's question is Option A, which states the cross-section would show larger particles settling at the bottom and smaller particles on top. This is in accordance with the principles of sedimentation and graded bedding found in natural depositional environments such as rivers or underwater avalanches like turbidity currents.