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A DNA molecule is composed of two strands. The structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands twisted around each other Each strand has a backbone made of alternating sugar the four nitrogenous bases in a dna are  adenine, cytosine, guanine, and thymine,.Complementary pairs of four nitrogenous bases in DNA adenine and thymine, cytosine and guanine,  By a dotted line are specified hydrogen bonds in these pairs, adjacent nucleotides are linked by a phosphodiester bonds

Explanation:

i hope this is right it took me awhile to figure this out

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: