21. Transfer of infection from cell to cell occurs mainly by direct transfer of virions via

A. plasmodesmata
B. ectodesmata
C. protonemata
D. none of these

22. Intracytoplasmic inclusion bodies are found in cells infected with

A. Rabies virus
B. Vaccinia virus
C. Fowlpox virus
D. all of these

23. What is the function of positive-strand in double-stranded RNA viruses?

A. Synthesis of protein
B. Production of ribosomes
C. Both (a) and (b)
D. None of these

24. Which of the following virus is transmitted by the respiratory route?

A. Rhinovirus
B. Coronavirus
C. Measles virus
D. All of these

25. The predominant lipid substance found in the viral envelope is

A. phospholipids
B. glycolipids
C. neutral fat
D. all of these