Globalized evolution...... but I might be wrong
<h2>DNA </h2>
Explanation:
1) Experiment done by Griffith:
- Griffith used two related strains of bacteria, known as R and S
- R bacteria were nonvirulent, meaning that they did not cause sickness when injected into a mouse whereas mice injected with live S bacteria developed pneumonia and died
- Griffith tried injecting mice with heat-killed S bacteria (that is, S bacteria that had been heated to high temperatures, causing the cells to die), the heat-killed S bacteria did not cause disease in mice
- When harmless R bacteria were combined with harmless heat-killed S bacteria and injected into a mouse, not only did the mouse developed disease and died, but when Griffith took a blood sample from the dead mouse, he found that it contained living S bacteria
- Griffith concluded that the R-strain bacteria must have taken up what he called a transforming principle from the heat-killed S bacteria, which allowed them to transform into smooth-coated bacteria and become virulent
2) Experiment done by Avery:
- Avery, McCarty and MacLeod set out to identify Griffith's transforming principle
- They began with large cultures of heat-killed S cells and, through a long series of biochemical steps progressively purified the transforming principle by washing away, separating out, or enzymatically destroying the other cellular components
- These results all pointed to DNA as the likely transforming principle but Avery was cautious in interpreting his results
- He realized that it was still possible that some contaminating substance present in small amounts, not DNA, was the actual transforming principle
3) Experiment done by Hershey and Chase:
- Hershey and Chase studied bacteriophage, or viruses that attack bacteria
- The phages they used were simple particles composed of protein and DNA, with the outer structures made of protein and the inner core consisting of DNA
- Hershey and Chase concluded that DNA, not protein, was injected into host cells and made up the genetic material of the phage
Answer:
An experiment where an antibiotic is tested against bacteria. The antibiotic can vary in its concentration for example, different amounts are applied to a sample of bacteria to see if it is affected by the action of the antibiotic and if so, in what concentration. So, the independent variable is the concentration of antibiotic while the dependent variable is the survival (or not) of the bacteria.
Explanation:
An independent variable is a variable that represents a quantity that the scientist modifies in an experiment. A dependent variable represents a quantity whose value depends on how the independent variable is modified. This is the variable being studied and measured.
So, an example of this applied to bacteria or viruses could be:
<u>An experiment where an antibiotic is tested against bacteria</u>. The antibiotic can vary in its concentration, different amounts are applied to a sample of bacteria to see if it is affected by the action of the antibiotic and if so, in what concentration. So, the independent variable is the concentration of antibiotic while the dependent variable is the survival (or not) of the bacteria.
To complete the experiment, an antibiotic whose effect is already known can be used as a positive control. That is, it is already known to kill the bacteria. And as a negative control you can simply use water, which has no effect and is known not to kill the bacteria. In this way, we validate the results and make sure that there is not something else that is affecting the bacteria and that only the antibiotic being studied has an influence.
Answer: (c) skeleton
Explanation: The musculoskeletal system is made up of the body's bones (the skeleton), muscles, cartilage, tendons, ligaments, joints, and other connective tissue that supports and binds tissues and organs together.
