What differs among dna structures of different species? a) the base pairs b) the nucleotide structure c) the types of amino acids used to make proteins d) the arrangement of the nucleotides within genes

D)the arrangement of the nucleotides within genes

Explanation:

De-oxy ribo nucleic acid that is basically a polymer of nucleotides. Nucleotides are composed of three basic units: a de-oxyribose sugar unit, a phosphate group and nitrogenous bases that can be Adenine, Gunanine, Thymine and Cytosine.Adenine always pairs with Thymine and Guanine always pairs with Cytosine.

This is a universal composition of DNA in each and every living organism. The genes are a segment of DNA that contain specific sequence of nucleotides and encode for a specific trait of organism such as height, weight, eye color etc. The sequence of nucleotides expresses the trait in the form of protein product during the process of Translation. The products of translation are amino acids and every amino acids encode for a specific protein  in almost  all living organisms.

So, what differs in the specie is the sequence of nucleotides in genes. Infact this is the nucleotide sequence which brings evolution in organism and organisms evolve to form new specie with the passage of time. One major cause of change in nucleotide sequence is mutations due to which the organisms change with time.

Suppose the sequence of nucleotide of specific gene in organism A is

AAAAATTT

However in other specie organism B of same specie is:

TAAAATTT

This means only mutation of one base changed the gene in organism B and also its product called protein.

Hope it help!

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