Precision is a. the degree of exactness in a measurement b. the degree to which a measurement approaches a standard value c. the degree to which a measurement misses a standard value d. the degree of accuracy in a measurement

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.