What does 'Red' indicate in the $IUCN$ Red List $(2004)$?

Why is the conservation of biodiversity considered an international issue?

How many gymnosperm species are facing the threat of extinction (in $\%$)?

The current rate of species extinction is estimated to be $.........$ times faster than the pre-human extinction rate.

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

Loss of biodiversity in a region may lead to all of the following,except: