If a dna molecule is compared to a spiral staircase, what parts make up the steps?
sugar and nitrogen base
pairs of nitrogen bases
sugar and phosphate
pairs of sugars

The correct answer would be pairs of nitrogen bases.

DNA (deoxyribonucleic acid) is a double helical structure formed by two strands of DNA.

Deoxyribose sugar and phosphate are linked with phospho-di-ester bond and serve as the backbone of the DNA strands.

Nitrogenous bases are attached to the sugar with the help of glycosidic bond.

Nitrogenous base of one strand forms hydrogen bonds with the nitrogenous bases of the other strands to provide the stability to the structure.

a. as the temperature increases, the kinetic energy of the gas molecules increases & the molecules move faster & further away from each other.

b. if you decrease the temperature of a fixed amount of gas at constant pressure, the combined gas law reduces to charles's law. in this case, volume will also decrease.

hi, natural selection of the peppered moth during the industrial revolution in 19th-century england is an example of an outlier in the study of evolution. during this time, pollution from factories filled the forests, coating trees in a layer of soot—turning white trees black

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