Topsoil erosion is such a large problem because __________.
the developed world depends on crops grown in topsoil
it exacerbates climate change and global warming
topsoil is found in such small quantities on the Earth’s surface
the developing world depends on crops grown in topsoil
topsoil takes a long time to replenish
The practice of "slash and burn" is widely considered to be __________.
found in high mountainous regions
a relatively new invention
not sustainable
typical for tropical forests