Final answer:
Hepatitis B (HBV) helps Hepatitis D (HDV) by providing the required replication machinery.
Step-by-step explanation:
Hepatitis B (HBV) helps Hepatitis D (HDV) by providing the required replication machinery. HDV is considered a defective virus because it requires HBV to complete its life cycle. HDV piggybacks on HBV by using the HBV envelope to enter the host cells. Once inside the host cell, HDV uses the HBV RNA polymerase to replicate its own RNA genome. Therefore, HBV infection is a prerequisite for HDV infection.