Griffith's experiment worked with two types of pneumococcal bacteria (a rough type and a smooth type) and identified that a "transforming principle" could transform them from one type to another.
At first, bacteriologists suspected the transforming factor was a protein. The "transforming principle" could be precipitated with alcohol, which showed that it was not a carbohydrate. But Avery and McCarty observed that proteases (enzymes that degrade proteins) did not destroy the transforming principle. Neither did lipases (enzymes that digest lipids). Later they found that the transforming substance was made of nucleic acids but ribonuclease (which digests RNA) did not inactivate the substance. By this method, they were able to obtain small amounts of highly purified transforming principle, which they could then analyze through other tests to determine its identity, which corresponded to DNA.
C is the answer just did it
The most appropriate microscope for studying the internal parts of the cell is ELECTRON MICROSCOPE. The correct option is B.
Electron microscope, which is a compound microscope is usually used to study the internal environment of the cell because of the easiness with which one can easily distinguish the cell organelles from one another. Electron microscope gives great clarification of the cellular components and allow scientists to observe minute details about cellular structures. Electron microscope usually magnify specimens to one million times of their real sizes.
Answer:
Variation can be acted on by natural selection.
Explanation:
Variation are the difference that exist in the organism in terms of the body size and can be acted upon by natural selection.
Natural selection could act on the owl body size, favor the selection of owl with small body size especially when resources available are limited and can only sustain small number of individuals leading to availability of owl with small body size in such area and a gradual reduction in the number of owl with large body size.
Answer:
C. Independent variable
Explanation:
The independent variable in an experiment is the variable that the experimenter manipulates or changes in order to effect a measurable response in the dependent variable.
According to this question, an experiment is conducted to determine what concentration of disinfectant is most effective in killing bacteria. The independent variable is the CONCENTRATION OF DISINFECTANT because it is the variable being changed or manipulated.
