Answer:
The answer is "decreases the number of bases in the sequence".
Step-by-step explanation:
Please find the complete question in the attached file.
The deletion mutation has been the retraction of a gene encoding base which alters the read-frame with codon it beyond mutation point. Its mutation or replacement includes the substitution of a framework with another base, throughout this situation the diagram describes the number of bases in the sequence belonging to the "X" marked area as the comparison of deletion and replacement mutations.