Discovery In 1928 it was discovered by Frederick Griffith in an experiment generally known as transformation.
Experiment
In his experiment he considered two strains of <em>streptococus pneumonia,</em> one was R-type which was non-virulent and cause no disease in mice, other was virulent and S-type which cause disease and at last death of mice.
This experiment was comprised of four steps which are as follow:
Step 1: First he injected living strain of S into mice, after sometime mouce died.
Step 2: He injected living strain of R into mice, the mice alive as he did not got any disease.
Step 3: He injected heat killed strain of S into mice and mice remain alive.
Step 4: He mixed living R strain with heat killed S strain and then inject into mice. As a result the mice died.
Conclusion: It was found that genetic material from heat killed S stain were transferred to living R (non-virulent) strain, as a result R become virulent and cause the death of mice.
I think that the Risk assessment depends on medicine. Here's some extra details: the PROCESS by which HAZARD, exposure and risk are determined. The four steps of risk assessment are Hazard identification<span>Dose-response assessment
Exposure assessment
Risk characterization</span>
3. Autotrophs produce organic molecules. I think 4 is cellular respiration cannot occur without photosynthesis
These are the thykloid and the stroma