4.1
renewable resource
Elements plants require
Fertilizers
erosion
terraces
desertification
deforestation
reforestation
4.2
arid/semiarid
watershed
aqueducts
aquifers
desalinization
modern water treatment
acid rain
inversions
global warming/ global climate change
4.3
nonrenewable resource
minerals (4 properties)
metallic vs nonmetallic
malleable
4.4
Nonrenewable energy resource
fossil fuel
petroleum
coal
natural gas
renewable energy resource
water, wind, sun, geothermal
?nuclear energy
