An atom has 6 electrons, 6 protons, and 6 neutrons. you can tell that this atom belongs to the element because

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

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.