Answer:
One
Explanation:
Sodium (Na) has one valence electron so it gets one dot.
The aquifer which will be most effective in purifying polluted ground water is AN AQUIFER COMPOSED MAINLY OF SAND.
An aquifer refers to a zone of permeable rock strata which transmit ground water freely. An aquifer must be permeable and porous. Ground water can be extracted from an aquifer by using a water well.
Because the organisms consume the departed