What will be the suitable for blank-“a”

Paragraph for question 13 to 16 Mutations are alterations in the DNA sequence that can occur in various forms, such as point mutations, where a single base is changed, or deletions and insertions, which result in the loss or addition of DNA segments. Substitutions involve the replacement of bases, while inversions reverse a DNA segment. Frameshift mutations, caused by insertions or deletions, disrupt the reading frame of genes. When a mutation leads to the replacement of one amino acid with another in a plant protein, it is known as ”a” . Mutations play a significant role in plant breeding, as they can introduce beneficial traits, enhance b , and improve crop resistance to diseases or environmental stresses.