What is the dependent variable and what is the independent variable in this?

mountains can affect the climate of nearby lands. in some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert. much of airborne moisture falls as rain on the windward side of mountains.

explanation:

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.