Two key experiments to prove that DNA is genetic material are: the toxicity of pneumococcus （肺炎球菌） in mice and the infection of

A、

Re-isolatedDNAfromtheinfectedorganismasthepathogenicagent（致病剂）ofthedisease

DNAmutation（突变）causeslossoftoxicity

Exogenous（外源）DNA(notprotein)absorbedbyanorganismchangesitsgeneticpotential

DNAcannotbetransferredbetweenorganisms,soitmustbeaconservative（保守的）moleculee  colibyT2phage（T2噬菌体）.Themainargumentevidence（论点证据）inthesetwoexperimentsis（）.