Which of the following is not an environmental consequence of using fossil fuels?
A. A worldwide infrastructure extracts, processes, and transports
fossil fuels.
.
B. Burning fossil fuels can release greenhouse gases into the
atmosphere, which contribute to global warming.
C. Wildlife habits can be disturbed when fossil fuels are extracted.
D. Chemical byproducts from burning fossil fuels can cause air
pollution.

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.

particle   p is an electron and particle q is a neutron