A particle which expresses the relation of connection or addition. It is used to conjoin a word with a word, a clause with a clause, or a sentence with a sentence.
one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
the blood group whose red cells carry the A antigen
any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
the basic unit of electric current adopted under the Systeme International d'Unites
a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
(biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
the 1st letter of the Roman alphabet