Acid contains. a) h^+. b)oh^-

An acid is a solution with more H+ ions than OH- ions. An acid is any compound that yields hydrogen ions (H+) or hydronium ions (H3O+) when dissolved in water.

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.