When a base substitution mutation occurs, one nucleotide in a replicating dna sequence is substituted for another, which results in the production of a mutant strand of dna. the result of the mutation depends on how the substituted nucleotide base alters the string of amino acids coded by the mutant dna. the three types of base substitution mutations are nonsense mutations, missense mutations, and silent mutations. each type is defined by how it affects protein synthesis?

A point mutation is a mutation that affects only a single nucleotide of a nucleic acid. They involve substitution of one base for another which changes the complementary base as well in DNA, they may also involve insertions and deletions of a single base pair. I therefore think the point mutations in a DNA sequence may profoundly have an effect on the synthesis of proteins, or may also have no effect on protein synthesis at all. These mutations can be beneficial to an organism, however they are more commonly neutral or harmful. 

The correct answer to this question would be c

The short-term effect of tar on the body is increased blood pressure.