In his transformation experiments, what did Griffith observe? Group of answer choices a. Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

b. Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. Mutant mice were resistant to bacterial infections.

c. Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.

d. Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.

The correct answer is a. mixing a heat killed pathogenic strain of bacteria with a living non pathogenic strain can convert some of the living cells into the pathogenic form.

Explanation:

Griffith proved that DNA is the genetic material in some organism. To do this he described the process of transformation in which the heat killed pathogenic bacteria when mixed with a non pathogenic bacteria can convert the non pathogenic strain into pathogenic one. This principle is called transformation.

The transformation of non pathogenic strain into pathogenic one occur due to the uptake of DNA of the heat killed pathogenic bacteria by the non pathogenic strain.