What are the limitations of gina’s model?

 Initial research suggests that a new animal species that’s entered the area caused the damage. So, Gina draws a model to show her colleagues what’s happening. Further research suggests that the animal has carried a bacteria that has infected the trees, causing the damage. What are the limitations of Gina’s model?
It doesn’t take all factors into account.
It isn’t drawn to scale.
It’s a mathematical model, not a conceptual model.
It needs to be a physical model, not a conceptual model

Which one is the bolded word? It could be collective if the bolded is lacrosse team, and indefinite if its photograph.