You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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.

Steps: (1) Solar radiation reaches Earth's atmosphere (2) Some is reflected back into space (3) The rest of the energy is absorbed by land and oceans, heating the Earth (4) Some of this heat is trapped by greenhouse gases in the atmosphere (5) Human activities such as burning fuel are increasing the amount of greenhouses gases (6) This causes more heat radiation to stay trapped in our atmosphere (7) The Earth's temperature rises  
Where does the following step fit into the given list of steps: Heat radiates from Earth to space 
Solution:  After step 3. 
Why? The correct answer is 'After step 3'. The given step is 'Heat radiates from Earth to Space'. Step 3 introduces a new concept of generated heat. Step 4 mentions that the heat is trapped into the atmosphere. In order for the heat to get to the atmosphere, the heat must radiate from Earth to space. Therefore, the correct answer is 'After step 3.'

New input: Steps: (1) Enters the lungs (2) The oxygen fills the sacs in your lungs (3) Carbon dioxide is removed from the lungs and exhaled (4) The oxygen is pass throughout your body.  
Where does the following step fit into the given list of steps: Air is taken through the mouth 
Solution:
 Before step 1. 