In gene therapy, which vector is commonly used to deliver functional genes into a patient's cells?

Choose a correct option for the uses of PCR technique in diagnosis

I. It is used to detect HIV in suspected AIDS patients

II. It is used to detect mutations in the genes in suspected cancer patients

III. It is used to detect swine flu in human beings

IV. It is used to detect different common diseases in pigs, sheep and cow

V. It is a good technique to identify many other genetic disorders

Which of the above statements are correct?