Research has demonstrated that neural stem cells have an impaired ability to differentiate into functional neurons when subjected to ethanol. They found out that treating cultured neural system impairs their ability to differentiate in functioning neurons. With this impairment it seems to be united with aberrant, dense methylation and loci which are active in normal tissue.
Balanced forces are forces that are equal in force but opposite sides. Mary would need to push on the opposite side of Trey with the same force of 30N. (I provided a photo to visualize)