In Fredrick Griffith's classic experiments,
◦ mice injected with strain R cells died of pneumonia.
◦ mice injected with strain S cells died of pneumonia.
◦ mice injected with live strain R cells and heat-killed strain S cells died of pneumonia.
◦ mice injected with strain S cells, or live strain R cells and heat-killed strain S cells died of pneumonia.
◦ mice injected with strain R cells, or live strain R cells and heat-killed strain S cells died of pneumonia.