What does the number of differences in rRNA sequences between two species represent?

You have sequenced the genome of the bacterium Salmonella typhimurium and find a protein that is 100 percent identical to a protein in the bacterium Escherichia coli. When you compare nucleotide sequences of the S. typhimurium and E. coli genes, you find that their nucleotide sequences are only 87 percent identical. How would you interpret the observations? Please make sure to select ALL correct answer options. Because genetic code is redundant, changes in the DNA nucleotide sequence can occur without change to its encoded protein. Due to the flexibility in the third positions of most codons, the DNA sequence can accumulate changes without affecting protein structure. Natural selection will eliminate many deleterious amino acid changes. This will reduce the rate of change in the amino acid sequence and lead to sequence conservation of the proteins. Protein sequences are expected to evolve and diverge more slowly than the genes that encode them.

When comparing evolutionary similarities between different genes within a gene family, it is usually more straightforward to compare genes by using the protein sequences of gene products rather than DNA sequences of the genes themselves. Explain why this is the case. (Include 4 succinct points at least)

Explain how the wobble hypothesis enables organisms to encode fewer tRNA molecules