Which compound has the highest boiling point?
nacl
h2o
o2
c6h12o6

NaCl

Explanation:

You could just look up the boiling points and compare but you can look for the ionic compounds because ionic compounds tend to have higher boiling points than covalent compounds. NaCl seems to be the only ionic compound.

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.