As the name suggests, proteases will be the enzymes which will catalyze the reactions of proteolysis. Proteolysis can be described as the process of breaking proteins into amino acids and simple peptide bonds.
DNases will catalyze the reactions for breaking down or degrading DNA. The DNase does this by breaking the phosphodiester bonds present in the backbone of the DNA.
RNases will be the enzymes which will catalyze the breaking of RNA molecules.
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)
