Sewage sludge can find a second life on farm fields. Here's how it's made
What goes down your toilet can end up on farm fields across the United States. Biosolids, or sewage sludge, are the solid ...
BBC3y
The rock cycle
These include weathering, erosion, transportation and sedimentation ... rocks are broken up by the roots of plants. They can also be broken by animals burrowing into them. Another process of ...