Which combined effect is most likely due to deforestation along river banks?

Correct answer: Soil erosion, increased silt and flood risk

Trees along river banks protect the ground in several ways. Their roots hold soil particles together, while trunks, leaves, and plant litter slow the movement of rainwater. When trees are removed, bare soil is more easily washed into the river. The extra soil becomes silt, making the river channel shallower and reducing its ability to carry floodwater. Faster surface runoff can then increase the chance and severity of floods.

Option D is correct because it combines the linked effects: more soil erosion, more silt in the river, and greater flood risk. The other options describe impossible or unrelated results. Water does not permanently freeze merely because bank trees are cut, sea tides do not end, and a river cannot normally flow uphill. Therefore, D is the most likely combined environmental effect.