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.
The correct answer would be
C.) <span>Polio Vaccination.</span>
Answer: One thing that is NOT true that concerns conifers is <u>they have motile sperm. </u>
Explanation:
Conifers are a seed plant. They are usually trees that bear cones and they have vascular tissues. They are classified as gymnosperms. The living confers are all woody plants.
The trees that are conifers are;
- Junipers
- Cedars
- Cypresses
- Firs
- Kauris
- Redwoods
- Spruces
- Yews
The colors of these conifers vary and include colors such as rainbow, bronze, yellow, blue, and red.
Explanation:
Fixed sample size:
In this fixed sample size the data is studied and checked in order to find a relationship. The benefits it is easy to produce, and with it less reliable outcomes can be given.
Sequential procedures:
→Sequential procedures helps while we are collecting the data.
→At an interim analysis, data collection can be stopped whenever the results are convincing enough to conclude an effect is present.
→Or otherwise the more data can be collected, or if needed the study can be terminated whenever it is extremely unlikely the predicted effect will be observed if data collection would be continued.
→In this two or more blocks of different sizes are prepared for testing.
→Pros being it provides better results and is less time taking, as we can stop once the relation is seen, con being it is difficult to perform.