The last $20$ years have witnessed the disappearance of $.............$ species.

According to $IUCN$,when a taxon is facing an extremely high risk of extinction in the immediate future,it is categorized as:

Provide information on the history of species extinction and state its effects.

According to $IUCN$ Red List $(2004)$ documents,how many species have become extinct in total?

If the current rate of species extinction continues,what percentage of all species on Earth will become extinct within the next $100$ years (in $\%$)?

Why is the conservation of biodiversity considered an international issue?