It focuses on its literal wording
Sales tax is what you're charged for. Businesses have to pay taxes annually, so they tax every sale.
B. canals. the early people built canals to water their crops.
The most important resource would be water.
They are fearful about "runaway" conventions making unwanted changes.
The process of constitution change is a political process and therefore there is always a risk of run away conventions coming up with unwanted and sometimes undesirable changes.