<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:
student 4 bcoz thymine is replaced by uracil in RNA
Baroreceptors. These are found in the carotids and aortic arch. They respond to pressure exerted on the vessels.
Answer:
D. A hurricane carries ocean water across the coast and damages houses of people.
Explanation:
This question is looking for a statement that shows the interaction of an atmosphere, hydrosphere and biosphere. Firstly, atmosphere refers to the layer of the air that surrounds the earth i.e it pertains to air. Hydrosphere refers to the part of the earth occupied by water bodies e.g sea, river, ocean etc. i.e. it pertains to water.
Biosphere is the part of the earth that has to do with life i.e. it pertains to living organisms e.g plant, animal, human etc.
Based on the definition of each component, option D truly shows the relationship/interaction of the three components mentioned. That is, A hurricane (represent part of the atmosphere because it has to do with air) carries ocean water (represents hydrosphere because it involves water body) across the coast and damages houses of people (represents biosphere because it talks about living humans).
