What is volume?
a. half of the density of a substance
b. the amount of matter in a substance
c. twice the amount of mass of a substance
d. the amount of space a substance takes up

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

answeridentity;