How many of the following statements are correct w.r.t. virus ?
(a) They are obligate intracellular parasites.
(b) They are inert outside their specific host.
(c) Virus can be crystallized.
(d) No virus contains either DNA or RNA.
(e) The protein coat called capsid is made up of small subunits.

Viruses are obligate parasites.
They are inert outside their specific host cell.
W.M. Stanley (1935) showed that viruses could be crystallised and crystals consist largely of proteins. 
No virus contains both RNA and DNA.
The protein coat called capsid made of small subunits called capsomeres, protects the nucleic acid.