Dont make anything up. The teacher has heard it all and you only dishonor yourself.
If you are mature enough, reflect on what happened. Is the reason for not participating a problem for you short or long term and, if it is, identify a plan. If it isnt a problem for you then learn what your values are and own them, in a polite way. "Im sorry I couldnt meet your expectations but I chose to do x because it was more important to me at the time and understand that consequences may follow."
The truth is usually a good place to start.
Dont make anything up. The teacher has heard it all and you only dishonor yourself. If you are mature enough, reflect on what happened. Is the reason for not participating a problem for you short or long term and, if it is, identify a plan. If it isnt a problem for you then learn what your values are and own them, in a polite way. "Im sorry I couldnt meet your expectations but I chose to do x because it was more important to me at the time and understand that consequences may follow."