Concept:Sedimentation separates soil particles by size, with heavier particles settling at the bottom.
Explanation:In the experiment, soil is mixed with water and allowed to settle.
Larger and denser particles sink faster than lighter ones.
Thus, the lowest layer, labelled IV, is formed by the coarsest soil particles.
Among the options, sand is the heaviest and coarsest component.
Therefore, part IV is the sand layer.
Answer:B. sand
