Answer:
Option 3 DNA coding for rRNA changes relatively slowly.
Explanation:
The complete question is as follows:
Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?
- rRNA is never the nucleic acid chosen for comparisons.
- rRNA cannot mutate.
- DNA coding for rRNA changes relatively slowly.
- rRNA mutates rapidly.
- rRNA is traditionally the nucleic acid chosen for recent comparisons.
- rRNA is the ribosomal RNA which along with the ribosomal proteins forms the ribosomes which play an important role in protein synthesis.
- rRNA does not code for anything however, it is still the most abundant form of RNA found in most of the cells, covering for around 80% of the total RNA.
- The genes that code for rRNA are quite resistant to mutations and alterations and thus, the sequence of the rRNA is quite conserved.
- A reason for the conservation of the rRNA is that any alteration in its sequence makes it non functional.
- This key feature of the rRNA makes it useful for phylogenetic and taxonomical studies to investigate the relationship between organisms.
