Which information can be determined from the litmus paper tests? A Solutions 1 and 5 are both acids.
B. Solutions 2 and 8 are both neutral.
C. Solutions 3 and 6 are both bases.
D. Solutions 4 and 7 are both acids.

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.

a polar bond is formed when electrons are shared unevenly between atoms