The hole in the Ozone Layer
Molting occurs in all animals with exoskeletons, due to the fact that such animals cannot grow bigger than their shell without replacing their shell with a bigger one. That is the general idea
The ph . this affects it because the more ph there is the more enriched the soil is. it fluctuates according to environmental factors e.g acid rain
I believe it is called a Frameshift Mutation. Hope this helps :^)