I did challenge 1, where breeds need to reach a maturity age before reproducing. I did this to give in preparation of having my students add more conditions to their models, to better represent realistic science. I struggled with knowing if the conditions worked correctly, because reproduction can only follow a collision, when the breeds get more energy. To better check, I could increase the collisions and maturity age, see if the reproduction still waits until maturity, and then return those conditions to their original settings. I could use help from the SLNova blogs, to see how other teachers and students handle checking results.