- Natural resources are broadly classified as renewable or non-renewable (exhaustible). - Renewable resources replenish naturally over time (e.g., solar energy, wind, water, soil, forests). - Non- renewable resources are finite and do not replenish at a rate comparable to consumption (e.g., fossil fuels, minerals). - Soil is technically renewable through natural processes like weathering and decomposition, but this process is extremely slow (centuries to millennia to form a few inches of topsoil).