SOLUTION:
Step 1 ;
In this question, we are meant to select TWO options that have pairs of variables that exhibit linear relationships.
By definition,
The linear relationship between two variables is positive when both increase together; in other words, as values get larger, values get larger.
This is also known as a direct relationship.
The linear relationship between two variables is negative when one increases as the other decreases.
Step 2 :
The TWO options are:
OPTION A - side length and perimeter of 1 face
OPTION D - Area of 1 face and surface area.