Answer:
Pyrimidines
Uracil = 2,4-dioxy pyrimidine
Thymine = 2,4-dioxy-5-methyl pyrimidine
Cytosine = 2-oxy-4-amino pyrimidine
Orotic acid = 2,4-dioxy-6-carboxy pyrimidine
Polynucleotides
Nucleotides are joined together by 3'-5' phosphodiester bonds to form polynucleotides. Polymerization of ribonucleotides will produce an RNA while polymerization of deoxyribonucleotides leads to DNA.
https://library.med.utah.edu/NetBiochem/pupyr/pupy15.gif
Explanation:
The crust is the outermost layer of the planet
