A — СИНОНІМІЯ
a the basic unit of electric current adopted under the Systeme International d''Unites
a a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
WordNet
a (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
WordNet
a one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
WordNet