Background extinction refers to the normal extinction rate. These are species that go extinct simply because not all life can be sustained on Earth and some species simply cannot survive. Mass extinction is a widespread event that wipes out the majority (over 50%) of living plants and animals.
Answer:
an enzyme produced chiefly by certain bacteria, having the property of cleaving DNA molecules at or near a specific sequence of bases.
The amino acid sequence in protein from the gene fragment for botana curus
is the same with species Z that is valine, histidine, leucine, threonine, proline,
glutamine and glutamine. Meanwhile, species X and species Y has different amino
acid sequence compared to botana curus. Therefore, species Z is most closely
related to botana curus because both species has the same amino acid sequence
and has similar sized DNA fragments.
