In Fred Griffith's experiments, harmless R strain pneumococcus became lethal S strain pneumococcus as the result of which of the following? 1. horizontal gene transfer 2. transduction 3. conjugation 4. transformation 5. genetic recombination

1, 4, and 51. horizontal gene transfer, 4. transformation and 5. genetic recombination.

Explanation:

In Fred Griffith's experiments, harmless R (rough) strain pneumococcus became lethal S (smooth) strain pneumococcus as the result gene transfer from smooth to rough strain. Gene transfer is the process through which genes are transferred from one cell or organism to other, and after transfer, genetic recombination occurs. Griffith's this process is called as transformation.