Hich of these is not a reason that species become extinct?

The two main reasons why a species becomes extinct are a natural catastrophe (such as volcano eruption, earthquake, drought, flood) and evolutionary changes which mean that the fittest species survive. Environmental changes, competition with other species for food and habitat, hunting patterns changing, as well as successful breeding of predators or species which the animals depend on as a food source for their survival are all contributing factors to a species extinction.