All stable atoms are . a. positively charged, with the number of protons exceeding the number of electrons. b. negatively charged, with the number of electrons exceeding the number of protons. c. neutral, with the number of protons equaling the number of electrons. d. neutral, with the number of protons equaling the number of electrons, which is equal to the number of neutrons.

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.

the answer is 1 i believe