Arrange the following discoveries in chronological order:
a. First picture of virus
b. Viral growth cycle against E. coli
c. Field trials of vaccine against yellow fever virus
d. Isolation of RNA from TMV
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a, c, d, b
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d, b, a, c
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d, c, b, a
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d, a, b, c
C
Correct answer
Explanation
This is the correct chronological sequence. In 1936, J. D. Bernal, F. C. Bauden, N. W. Pirie isolated ribonucleic acids from TMV. In 1938, Max Theiler's vaccine against yellow fever was proved successful in field trials. In 1939, E. L. Ellis and Max Delbruck established the concept of one-step viral growth cycle for a bacteriophage active against E. coli and in 1940, Helmuth Ruska used an electron microscope to obtain the first pictures of a virus.