Answer:
Used the complete extract to incubate nonvirulent cells
Explanation:
Avery and his colleagues injected the extracts from a virulent strain of <em>Streptococcus pneumoniae</em> into the mice and observed that the mice died. They extracted the DNA from the heat-killed virulent strain of<em> Streptococcus pneumoniae.</em> RNAse and proteases enzymes were used to remove the RNA and proteins present in the extract.
This was followed by incubation of mice with DNA extract of virulent heat-killed bacteria and the live non-virulent strain to show that the DNA from heat-killed virulent strain transformed the live non-virulent strain to the virulent one. This was why the mice died of the infection.
However, to ensure that the DNA was present in the virulent cells, they used the complete extract from virulent bacteria without any treatment with RNAse and proteases to transform the nonvirulent cell. It was proved that the DNA was the genetic material for transformation.
Answer: yes I do believe the break up of peagaea had to do with the mass extinctions of some dinosaurs in such as the environment had changed for some and they weren’t able to cope it, it can also be the lack of food sources and predators. However with the Pangea there were new species of dinosaurs that had evolved which gave them a better survival then the first generations of dinosaurs when peangea was just started to appear
Explanation:
Stable ecosystems can be altered, either rapidly or slowly, through human activities, natural disasters, climatic changes. An ecosystem may be described as a community and its surrounding which includes non living organisms. Human activities such as deforestation, mining, dumping of wastes on the oceans alters and affects the ecosystem negatively and thus making the habitats unfavorable for the organisms. Natural disasters such as floods, tsunami and climatic changes may also alter the ecosystem.
C. the microscope needs to be protected from dust
As per <span>Mendel studied seven pea plant </span>traits<span>, each with two contrasting characters. He crossed plants with each of the seven contrasting characters and studied their offspring. Each original pair of plants is the P (parental) generation.
True !</span>
