Which of the following is the most important cause of animals and plants being driven to extinction?

Habitat loss and fragmentation are considered the most important factors driving animals and plants to extinction. Human activities, such as deforestation, urbanisation and conversion of natural habitats for agricultural or industrial purposes, result in the loss and fragmentation of natural habitats. This makes it difficult for animals and plants to fi nd food, shelter and mates. It also disrupts the ecological balance.
(1) Alien species invasion is also one of the four major causes of extinction of species, but it is not the most important factor in driving species to extinction. 
(3) Drought and floods are natural occurrences that have been happening for millions of years and, while they may affect the survival of some species, they do not necessarily lead to extinction.
(4) Economic exploitation is also a threat to some species, particularly those that are hunted or harvested for commercial purposes, but it may not be the most important factor driving extinction overall.