Rivers and streams erode the land as they move from higher elevations to the sea. Eroded materials can be carried in a river as dissolved load, suspended load, or bed load. A river will deeply erode the land when it is far from its base level, the elevation where it enters standing water like the ocean.
Antibiotics killed the bacteria that cause infection but they can also kill beneficial bacteria . thus Ms ABC developed a yeast infection and diarrhea after course of antibiotics because antibiotics distrub natural balance of beneficial bacteria in her intestine.