Nitrogenous bases are the parts of RNA and DNA that are involved in pairing up (see also base pairs). These include cytosine, guanine, adenine, thymine (DNA) and uracil (RNA).
... Cambridge Cornwall Barbara Hepworth Museum[?], St. Ives, Cornwall Penlee House, Penzance[?] Tate St. Ives[?] Cumbria Abbot Hall Art Gallery[?], Kendal[?] Beatrix ...