A hill is formed from fine, wind-blown sediment called "loess".  Is this an example of mechanical weathering, chemical weathering, erosion, or deposition?

Sediment from Yankton, SD is carried to down the Missouri River.  Is this an example of mechanical weathering, chemical weathering, erosion, or deposition?

Acidic groundwater breaks down the rock around it, creating a limestone cave.  Is this an example of mechanical weathering, chemical weathering, erosion, or deposition?

Tree roots grow through a rock.  Is this an example of mechanical weathering, chemical weathering, erosion, or deposition?

Water seeps into cracks in the sidewalk, and then freezes and expands to make the crack widen.  Is this an example of mechanical weathering, chemical weathering, erosion, or deposition?