Avery's experiments showed that bacteria are transformed by “transforming principle” – DNA.
When Griffit in his experiments showed that R-strain bacteria (non-virulent) could be transformed by the heat-killed S bacteria, and become virulent, scientists assumed that there is some kind of “transforming principle” that is involved.
Avery and his colleagues cultured heat-killed S cells and tried t separate cellular components that could possibly be that “transforming principle”. Molecule of DNA gave positive result in a chemical test and also when enzymes able to degrade DNA were introduced, the transforming activity was eliminated.
fossil y exsited during the same period a ammonite
Answer:
because existing cells divide to produce new cells
Answer:
Marine ecosystems are characterized by factors such as availability of light, food and nutrients. Other factors that affect marine ecosystems include water temperature, depth and salinity, as well as local topography. Changes in these conditions can change the composition of species that make up the marine community.
