Thank you it means alot if you help :)!

10.Semi-Solid

11.Liquid

12.Solid

13:Semi-Solid

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.

let that person have a turn to speak : )