How many Liters of a 4.5 M HCL solution can be prepared by using 250.0 mL of a 12.0 M HCl solution?

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.

im not exactly sure but i think its b!