AP BIOLOGY

Detailed explanation-1: -B. Silent mutations are a result of the redundancy (degeneracy) of the genetic code: This is false, as silent mutations are the result of a base substitution that has no discernible effect on the amino acid sequence of a protein.

Detailed explanation-2: -Insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion. However, such mutations are referred to as frameshift insertion or deletion mutations. So, the statement in option C is wrong.

Detailed explanation-3: -A substitution mutation is a type of replication error during DNA replication which places the wrong nucleotide or sequence of nucleotides in the wrong position. A type of substitution mutation, a point mutation, occurs which a single nucleotide is substituted.

Detailed explanation-4: -Single base substitutions are called point mutations, recall the point mutation Glu—–> Val which causes sickle-cell disease.