Describe biodiversity as the number of different species that live in an area

Describe the effects of untreated sewage and excess fertiliser on aquatic ecosystems

Describe how humans have increased food production, limited to: (a) agricultural machinery to use larger areas of land and improve efficiency (b) chemical fertilisers to improve yields (c) insecticides to improve quality and yield (d) herbicides to reduce competition with weeds (e) selective breeding to improve production by crop plants and livestock