The answer is: A decrease in the number of Trees
Woodpeckers are known for their use of finding food sources on the trucks of trees. They are also popularly own for beating their beaks against a tree trunk in order to provide vibrations and communicate with other woodpeckers.
Contrary to popular belief, they do not eat wood, but trees as a whole form an important part of their habitat.
Hence, the deforestation, cutting down of trees and urbanization can all lead to the decreasing number of woodpeckers in the ecosystem.
Since the early 20th Century two species of American woodpeckers are already considered extinct.
Explanation:
Fixed sample size:
In this fixed sample size the data is studied and checked in order to find a relationship. The benefits it is easy to produce, and with it less reliable outcomes can be given.
Sequential procedures:
→Sequential procedures helps while we are collecting the data.
→At an interim analysis, data collection can be stopped whenever the results are convincing enough to conclude an effect is present.
→Or otherwise the more data can be collected, or if needed the study can be terminated whenever it is extremely unlikely the predicted effect will be observed if data collection would be continued.
→In this two or more blocks of different sizes are prepared for testing.
→Pros being it provides better results and is less time taking, as we can stop once the relation is seen, con being it is difficult to perform.
The answer for this question is pairs of nitrogen bases
A.........................
