Fred Griffith Studied Two Strains of Streptococcus Pneumonia, One That

Multiple Choice

Fred Griffith studied two strains of Streptococcus pneumonia, one that causes a lethal infection when injected into mice, and a second that is harmless.He observed that pathogenic bacteria that have been killed by heating can no longer cause an infection.But when these heat-killed bacteria are mixed with live, harmless bacteria, this mixture is capable of infecting and killing a mouse.What did Griffith conclude from this experiment?

A) The infectious strain cannot killed by heating.
B) The heat-killed pathogenic bacteria "transformed" the harmless strain into a lethal one.
C) The harmless strain somehow revived the heat-killed pathogenic bacteria.
D) The mice had lost their immunity to infection with S.pneumoniae.