Not All Parents Put Babies to Sleep on Back. Dec. 7, 2009 -- Despite warnings that it is safest to place a baby to sleep on his or her back, the number of caregivers doing so has not increased in recent years, according to a new report.
Nucleic acids are polymers of individual nucleotide monomers. Each nucleotide is composed of three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base. Only two 5-carbon sugars are found in nature: ribose and deoxyribose.
1 The two principal types of nucleic acids are deoxyribose nucleic acid (or deoxyribonucleic acid, DNA) and ribose nucleic acid (or ribonucleic acid, RNA). 2  DNA is a polymer. 3  Individual monomer units are called nucleotides.