Which of the following does not generally speed up a reaction?
a. increasing the activation energy
b. adding more heat
c. shaking the container holding the reaction
d. stirring rapidly

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.

the answer to your question is c