Extinction is a natural phenomenon. It is estimated that 99% of all species that ever lived are now extinct. Why then do we say that we are now experiencing an extinction (loss of biodiversity) crisis?
A) Humans are ethically responsible for protecting endangered species.
B) Scientists have finally identified most of the species on Earth and are thus able to quantify the number of species becoming extinct.
C) The current rate of extinction is high and human activities threaten biodiversity at all levels.
D) Humans have greater medical needs than at any other time in history, and many potential medicinal compounds are being lost as plant species become extinct.
E) Most biodiversity hot spots have been destroyed by recent ecological disasters.
Answer: C) The current rate of extinction is high and human activities threaten biodiversity at all levels.
You might also like to view...
True or false: The same strand in a DNA double helix is used as the template strand for transcription of every gene in a given chromosome
A. true B. false
The following products diffuse into the lacteal
A) triglycerides B) monosaccharides C) ions D) amino acids
A DNA microarray is a tool that owes its existence to earlier genomics investigations. What essential contribution of genomics makes microarrays possible?
A) recently improved RNA sequencing technologies B) continuously improving methods of gene cloning C) more efficient techniques for cDNA synthesis D) knowledge of which DNA sequences to synthesize for the array
When can we say that atom has no vacancy, or the atom is full?
A. An atom's outer shell is filled with electrons B. An atom's inner shell is filled with electrons C. An atom's outer shell is filled with neutrons D. An atom's outer shell is filled with protons E. An atom's inner shell is filled with protons