Answer:
Watson and Crick were able to develop a more accurate molecular structure because they had access to x-ray crystallography! Pauling didn't actually failed, he just did't have the same means!
Explanation:
By the way, is now known that the real discovery of DNA molecule was made by Rosalind Franklin. Any doubts you can send me a message!
The correct answer is: introns
Processing of mRNA is process that occurs only in eukaryotic cells. After the transcription, newly formed mRNA molecule is called and it must be processed into a messenger RNA (mRNA). Processing includes:
• Addition of a 5' cap to the beginning of the RNA
• Polyadenilation- addition of a poly-A tail (tail of A nucleotides) to the end of the RNA
• Splicing- removal of introns and linking the exons
After these steps mRNA is mature and used for the further steps (e.g. translation).
Sometimes some genes are alternatively spliced.
The cell wall protects the cell from other bacteria and virus attacks.I also forms a protective suit around the cell.