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.
Answer:
At the very bottom
Explanation:
When examining a cross section of rock layers, the oldest layer is on the bottom. This is because over time, newer rock layers continued to form on top of the oldest one.
B cells mature in the bone marrow, which is at the core of most bones It recognises invaders by the shape of molecules -antigens- on their surfaces. With the help of T cells, B cells make proteins called antibodies. The antibodies will help your body become aware of intruders.
Answer:
An increase in the combustion of fossil fuels
Explanation:
Because they are prokaryotic cells.