What are some examples of human activity which might affect biodiversity?
Deforestation, removal of important species e.g. Wolves, Beavers. Litter, poisoning the ground and water via fertilisers, pesticides. Construction projects (be it a house or a dam).
Biodiversity is how diverse a select area is in organisms, be them animal, fungi or plant.
Humans have long effected this biodiversity ever since we started changing our environment, be it from cutting woods down to make farmland or to get firewood, or from run off from mining, or pesticides to get rid of insects which decimate our crops, these all have affected our environment and its biodiversity, one way or another.