A farmer is analyzing cross-sections of his land to determine where to build a well. Which phrase describes the best area to dig down to the groundwater?

where the saturated zone is 15 meters deep
where the water table is 100 meters deep
where the unsaturated zone is 50 meters thick
where there is a 25-meter thick clay layer at the surface

i think that d. wind is the answer.   i missed the question when i answered a. currents.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.