What is the role of nucleotides in dna structure?

Nucleotides help form the backbone of DNA and RNA.

Nucleotides are subunits that are linked to form nucleic acids. All nucleotides are composed of three parts: a five carbon sugar, a phosphate and a nitrogen - rich structure called a nitrogenous base.

It is the phosphate group that that makes the nucleotide so critical in DNA structure. By linking the phosphate of one nucleotide to carbon 3 of the sugar in the neighboring nucleotide, a DNA polymer is made. The repeating pattern of phosphate, sugar, then phosphate again is commonly referred to as the backbone of the DNA or RNA molecule.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.