Final answer:
A slow meandering river is least likely to transport large particles, since it lacks the energy to carry them. Fine and medium particles may still be transported, but larger sediments will settle.
Step-by-step explanation:
A slow meandering river is least likely to be transporting large particles such as gravel. The energy required to carry large particles is greater than what a slow-moving river can provide. Sediment transportation depends on the velocity of the water; as the speed of the river decreases, its ability to carry large sediments diminishes.
In the context of river systems and sediment transport, fine particles like silt and clay are likely to remain suspended in slow-moving water and can be transported further downstream. Medium-sized particles such as sand may also travel with slow currents, but larger sediments like gravel will generally settle because the water doesn't have the necessary force to keep them aloft.