Remark
Before you do anything else, read what she did. She opened the refrigerator door slightly. What would you expect to happen especially on a summer day?
Would you expect the temperature to go up? Warm air is heating up the refrigerator in side and the graph shows the temperature increasing. Is it a straight line or is it something else? It looks like it is increasing to start with and it is non linear.
Now she closes the door and refrigerator begins to cool down. The trip down is a straight line (linear). When that happens, you get your answer for this part of the graph, down and linear.
So the complete answer is door open, temperature rises and is non linear.
The door closes and the temperature falls and the line of the graph is linear.
C <<<<< Answer.
