What does occean salinaty refer to

The concentration of salt in seawater (salinity) varies with temperature, evaporation, and precipitation. Salinity is generally low at the equator and the poles, and high at mid-latitudes. The average salinity is about 35 parts per thousand.

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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.

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