185. The figure below shows steps A, B & C of replication of retrovirus. Select the option giving correct identification Retrovirus Viral RNA core Virus infects Viral protein normal cell coat Plasma membrane Animal cell Viral RNA is introduced into cell AL B C New viruses are produced Nucleus DNA New viruses can infect other cells (1) B-Incorporation of viral DNA into host genome with integrase enzyme (2) C-Production of new viral DNA by infected cell (3) A-Replication of viral RNA by protease enzyme (4) C-Viral RNA replication by reverse transcriptase enzyme 186. Safest method of cancer detection is (1) Biopsy (2) MRI (3) CT-scan (4) Radiography 187. Hepatitis-B vaccine is :- (1) Live vaccine (2) Subunit vaccine (3) Natural vaccine (4) Attenuated vaccine 188. Smoking increases.........content in blood and reduces the concentration of haembound oxygen? Fill the blank :- (1) CO (2) CO (3) Oxygen (4) Nitrogen 189. Tear in eyes form which barrier of innate immunity? (1) Physical (2) Physiological (3) Cellular (4) Cytokine 190. Total no. of polypeptide chains in IgM ? (1) 5 (2) 10 (3) 20 (4) 4