What are three examples of objects that are too big to be studied without models

Idon’t quite understand this problem

What type of relationship exists between the length of a wire and the resistance, if all other factors remain the same? o a. resistance is directly related to length. ob. resistance is directly related to the square of the length. c. resistance is inversely related to the length. d. resistance is inversely related to the square of the length. reset next

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly