True or False: The amount of water has and will always remain about the same?

In the world? I would say no, but at the same time there are a lot of variables to consider in this. But I'd say no. Just my opinion.

Explanation

False the amount of water on earth has decreased over the years

Explanation:

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.