Answer:
The correct answer is option - A. 0.
Explanation:
Producers are the organism that produces on their own. They do not depend on other organisms for their nutrition and energy such as green plants. They transfer energy and nutrition.
In the given scenario there is no producer present all are consumers of different levels. Cricket is a primary consumer, a spider is a secondary consumer and bird is the third consumer in this food chain.
Thus, the correct answer is option- A. 0.
<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
The given statement "Decreasing the rate of gene flow between two populations is likely to make the populations more different from one another." is False.
<h3>
What is gene flow?</h3>
- Gene flow refers to the processes by which genes are transferred from one group to another.
- Gene flow, which is a term used more frequently in anthropology, refers to the allelic change brought on by human movement.
- Gene flow would reduce the isolation that could lead to speciation by increasing population similarity and reproductive kinship.
- Gene flow significantly slows down speciation by recombining the gene pools of the groups and therefore repairing the growing variations in genetic variation that would have otherwise resulted in full speciation and the creation of daughter species.
Learn more about the gene flow with the help of the given link:
brainly.com/question/17190749
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