Task: Sentence Ordering
Input (English): Steps: (1) Sunlight passes through the glass into the greenhouse (2) The absorbed sunlight is converted to heat (3) The heat cannot escape the glass (4) The heat is trapped in the greenhouse (5) The hot air rises (6) The colder air at the top is pushed to the bottom (7) The colder air is then warmed by the floor and the plants.  
Where does the following step fit into the given list of steps: The plants and floor absorb the the sunlight 
Output (English):  After step 1.