(a) Habitat loss and fragmentation is the most common factor for extinction.
An example of habitat loss is the extinction of few primates out 620 primate species in tropical rain forest. 6% of the earth land surface now comprises of the tropical rain forests which were earlier 14% and are destroyed very fast.
Example for the fragmentation is the Amazon rain forest that leads to extinction of species which is being cut and cleared for soybean cultivation or for conversion to grasslands for raising beef cattle. This is the fragmentation of the land which leads to population declines.
Habitat loss and fragmentation reduce the amount of suitable habitat available for organisms. The separation of suitable sites adversely affects migration and reduces the biodiversity.
(b) The two ways of biodiversity conservation are ex-situ and in-situ conservation.
Ex-situ conservation means the protection of an endangered species outside its natural habitat within the care of humans. For example, biodiversity hotspots such as the Western Ghats and Sri Lanka, Indo- Burma and Himalaya.
In-situ conservation is the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of tree species. It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predators. Zoological parks, botanical gardens and wildlife safari parks serve this purpose. Seeds of different genetic strains can be kept for long periods in seed banks.