Many different types of mutations can occur within the body. An individual experiences a mutation that changes a base in a mRNA strand, but during translation the mRNA strand still creates the same protein. Which type of mutation is
responsible for the change in the mRNA base?

A. silent

B. missense

C. nonsense

D. insertion

A. Silent, The type of mutation responsible for changing a base in the mRNA strand, without changing the coding aminoacid or protein, is called a silent mutation.

Explanation:

In a silent mutation occurs the change of a nitrogenous base in one of the codons that encodes an aminoacid, without changing the aminoacid or altering the structure or function of the protein to be synthesized.

In this type of mutations the change of the base does not mean the change of the aminoacid, because some aminoacids can be coded with more than one codon. In the case of Leucine, the codons that encode it are CUU, CUC, CUG or CUA, so even if a base changes, the final protein will be the correct one.

For the other options:

the wires in the toaster turning red and the toast crisping and turning brown

the answer is b.) hydrogen bonds between bases.