Answer:
Since this is a question with multiple questions in them, I will provide the answer and an explanation when at all possible, or appropriate.
1. What would be the best use of a pie graph? C: Showing the most-liked ice cream flavors of students in one class.
The reason for this being the best answer is that pie charts allow to organize the results from research where there is only one variable being displayed. In this case, all we want to see is the visual data obtained on ice cream flavor preferences and compared. Thus a pie chart allows us to do that.
2. Imagine you are researching the forest in a specific national park. Which resource would be helpful for this research? The best answer is A: A pie graph showing how many of each species of tree is found here.
Again the reason is that we have only one variable, as per the purpose stated. We just want to see visually represented, the percentages of each type of tree within the forest being studied. Pie charts are the best here.
3. How does the model research report use statistics? The best answer here would be D: To inform the reader and move him or her to action.
Statistical data allows people reading a report, or an article, to see that there is mathematical, real, reliable, verifiable proof, that something being stated is real. Scientific papers, in order to prove their hypothesis, will usually utilize statistical data to do so, and this will generate reactions from readers better than simple subjective opinions.