The correct answer is B. A structure that is used to represent a complex system
Step-by-step explanation:
A scientific model is a structure or set of concepts that aim at representing a natural phenomenon or system. This means a scientific model is not created to be an exact copy of the system but rather to act as a representation, which helps scientists to explain or understand the functions and elements of a system. For example, by creating a model of a specific ecosystem, scientists can better understand the interactions between living organisms in the ecosystem, even though the model is not an exact model of the real ecosystem. According to this, a model in science is "A structure that is used to represent a complex system"