What is the purpose of DNA structure made of nucleotides

DNA is made up of molecules called nucleotides.

Its unique structure enables the molecule to copy itself during cell division. When a cell prepares to divide, the DNA splits down the middle and becomes two single strands. These single strands serve as templates for building two new DNA molecules - each a replica of the original DNA molecule.

answer: the answer is b

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.