It Is Estimated That 99% of All Species That Ever

Multiple Choice

It is estimated that 99% of all species that ever lived are now extinct.Why,then,do we say we are now experiencing an extinction (loss of biodiversity) crisis?

A) Humans are ethically responsible for protecting endangered species,but protection is limited.
B) Most of the species on Earth have been identified,so rates of extinction can be quantified.
C) The current rate of extinction is high,and human activities threaten biodiversity at all levels.
D) High human need for plant-based medicinal compounds is leading to plant species extinction.
E) Most biodiversity hot spots have been destroyed by recent ecological disasters,such as floods.