Answer:
First Question: in order to better explain what is happening during a phenomenon
Second Question: show beginning, middle and end if it fits the phenomenon; use zoom in bubbles to show the unobservable
Third Question: the type of material used to create the model
Step-by-step explanation:
First Question: You would not revise a model to "cover up evidence," that's scientifically immoral and should not be done, and showing off to other scientists is not the point of revising something.
Second Question: You should use more than one color to differentiate different parts of the model, but don't overwhelm it with color. There should be some labels in the model, so some writing is necessary.
Third Question: Inaccurate color representation does not technically limit a model unless color scheme is important, so this could be an answer, but not likely. A messy model limits a model because it makes it hard to read. Approximating shapes is a limitation because it portrays an incorrect representation of what system the model is of. The type of material used to create the model is most likely the right answer.