For each of the following, indicate whether the expected relationship between the two variables will be positive

Question:

For each of the following, indicate whether the expected relationship between the two variables will be positive (+), negative (-), or zero (0):
______a. Size of house and size of electric bill
______b. Height of parents and height of children
______c. Air humidity level and people's energy level
______d. Number of books read per year and age at which got first eyeglasses
______e. Hours spent at the beach and depth of tan