1. A
2. type A, group A, blood group, blood type, angstrom
3. angstrom unit, A, metric linear unit, vitamin A
4. antiophthalmic factor, axerophthol, A, fat-soluble vitamin, deoxyadenosine monophosphate
5. A, nucleotide, adenine
6. A, purine, ampere
7. amp, A, current unit, A
7. letter, letter of the alphabet, alphabetic character