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In 1928, Frederick Griffith published his work with two strains of Streptococcus pneumoniae and their abilities to infect and kill mice. He noted differences between an encapsulated S strain that appeared smooth when grown on agar plates and a non-encapsulated R strain that appeared rough by comparison when grown on agar plates. Using various combinations of living and heat-killed R and S strains, he demonstrated the process of transformation and proposed the existence of a transforming principle.

Based upon his experimental design, which strain or combination of strains of Streptococcus pneumoniae resulted in the killing of mice, demonstrating transformation?

A

Dead capsulated (S) strain alone.

B

Dead capsulated (S) strain + dead non-capsulated (R) strain.

C

Live non-capsulated (R) strain alone.

D

Dead capsulated (S) strain + live non-capsulated (R) strain.

E

Dead non-capsulated (R) strain alone.

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