Laughing gas can decompose into nitrogen and oxygen

Nitrous oxide decomposes into nitrogen and oxygen, according to 2 N2O (g) -> 2 N2 (g) + O2 (g). ... In an experiment, a stream of N2O is passed through a tube 25 mm in diameter and 20 cm long. The flow rate of the gas is 0.75 L/min.

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.

i think it's letter a.