6. The infected cells continue to reproduce themselves as well as the virus, and the mature virions are extruded from the cell surface continuously over a long period of time. This type of release mechanism is called a

A. productive infection
B. inductive infection
C. resultant infection
D. all of these

7. What kind of embryo is often used for viral assays?

A. Mouse
B. Rat
C. Cat
D. Chicken

8. The envelope of an enveloped virus is derived from

A. the mitochondrion of the cell
B. the cell membrane
C. the endoplasmic reticulum of the cell
D. none of these

9. The most popular indirect method of counting virus particles is by

A. hemagglutination assay
B. plaque-assay
C. counting plaque-forming units
D. colony counting

10. Which of the following viruses belong to family Hepadnaviridae?

A. Hepatitis A virus
B. Hepatitis B virus
C. Hepatitis D virus
D. All of these