Today , In this beautiful world - many species are vanishing day by day . They are in danger. This is due to because of we humans kill all the species. Disease, pollution and limited distribution are more factors that threaten various plant and animal species. If a species does not have the natural genetic protection against particular pathogens, an introduced disease can have severe effects on that species. For example, rabies and canine distemper viruses are presently destroying carnivore populations in East Africa. Domestic animals often transmit the diseases that affect wild populations, demonstrating again how human activities lie at the root of most causes of endangerment. Pollution has seriously affected multiple terrestrial and aquatic species, and limited distributions are frequently a consequence of other threats. Populations confined to a few small areas due to habitat loss may be disastrously affected by random factors.