Griffith concluded that in the presence of the dead S-type pneumococcus cells, some of the living R-type cells had been transformed into virulent S cells. These cells were able to grow in the bodies of the mice, causing pneumonia and multiplying in the blood. ... The DNA alone caused bacterial transformation.
Griffith introduced heat-killed 'S'- strain bacteria Streptococcus in to a mouse along with live 'R' strain bacteria. ... Some 'transforming principle' transferred from the heat-killed 'S' strain had enabled the 'R' strain to synthesise a smooth polysaccharide coat and become virulent.
In this experiments, Griffith injected mice in the lab with live R-type of bacteria. They did not suffer from the disease. ... He thus concluded that heat-killed smooth type bacterial caused a transformation of the living rough type bacteria. This experiment suggested that DNA and not proteins are the genetic material.
When the temperature increases there is more evaporation. When there is more evaporation the humidity increases due to more water molecules in the air. More humidity means more precipitation.