Which of the following statements is true a. elements are more complex than compounds
b. compounds can be broken down by physical means
c. compounds are composed of more than two different elements
d. ferrous sulfate cannot be broken down into simpler substances

unmm i think its d i am not sure sorry if I will wronge

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.