What are the chemical components of a dna molecule? ?

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

Which characteristic of water it form droplets? a. low specific heat b. nonpolar structure c. high surface tension d. ability to dissolve substances

Water is a highly important natural resource. which of these would be the best method to conserve water? a) drinking bottled water b) monitoring the ph of rivers c) treating and re-using wastewater d) testing nitrate levels in groundwater