The correct answer is B.
There's no statically significant association between the exposure and the disease. The risk ratio does not follow the normal distribution, even it does not depend on sample size in comparison groups. The natural rr is approximately normally distributed and is used to produce confidence interval which is for the relative risk.
1) Mutations are caused by changes in nucleotide bases. these altered base formed different amino acid depending upon nucleotide base sequence that code specific amino acid. ... even though some mutations, can have a more effect on amino acid coding, which can affect what kind of proteins are produced.
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