instruction:
Given a list of steps and an additional step, determine where the step fits into the original list of steps. A correct answer, correctly places the given step into the set of steps so that it creates a new plausible set of steps. Output must be formatted as 'After step n', where n is the step number after which the given additional step is to be inserted.
question:
Steps: (1) A virus enters a host body (2) The virus enters the cell (3) The virus uses the cell like a factory to make new copies of the virus (4) The new copies of the virus leave the cell (5) Infect other cells (6) The host gets sick as its cells are damaged.  
Where does the following step fit into the given list of steps: The virus has receptors that lock onto a target cell 
answer:
 After step 1. 


question:
Steps: (1) Human beings burn fossil fuels (oil, gas, etc.) (2) The make-up of the atmosphere changes (3) Some energy from the sun cannot escape back through the changed atmosphere (4) The earth begins to heat because of the extra trapped energy (5) Human beings cut down trees (6) Human beings do not re-plant the trees (7) Trees cannot help take the extra carbon dioxide from the atmosphere (8) The extra trapped energy starts to change the earth&#x27;s short term weather (9) Eventually the long-term climate patterns start to change  
Where does the following step fit into the given list of steps: Carbon dioxide from the burning fossil fuels enter the atmosphere 
answer:
 After step 1. 


question:
Steps: (1) An airline reservation is made (2) The passenger arrives early at the airport (3) The luggage is checked (4) The passenger waits in line (5) The passenger shows their identification and gets a boarding pass (6) The passenger goes to their gate (7) The passenger gets in line when it's time to board (8) The plane arrives at the destination (9) The passenger gets off the plane at their destination.  
Where does the following step fit into the given list of steps: The person boards the plane 
answer:

 After step 7.