Classify each of the following as a redox reaction or a non-redox reaction.
zn+cucl2 -> zncl2+cu hcl+naoh -> h2o+nacl 2co+o2 -> 2co2 so3+h2o -> h2so4

take a better picture and ill do it

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.