acid or anhydride acid or base acid or ester acid or salt acid or sodium acid other acid oxidase acid particles acid ph acid phase acid phosphatase acid phosphate acid pickling acid plant acid polymer acid polymerase acid polymers acid polypeptide acid position acid powder acid precipitation acid precursor acid precursors acid preparation acid present acid probe acid probes acid process acid produced acid produces acid producing acid product acid production acid products acid profile acid profiles acid protecting acid provides acid purification acid rain acid rain has acid ratio acid reaction acid reacts acid receptor acid receptors acid recovery acid reduces acid reflux acid reflux disease acid reflux symptoms acid residue acid residues acid resin acid resistance acid resistant acid rock acid salt acid salts acid sample acid samples acid sandoz acid scavenger acid scavengers acid secretion acid segment acid sequence acid sequence can acid sequence encoding acid sequence homology acid sequence of human acid sequences acid sequestrant acid serves acid should acid side acid side chain acid sites acid soap acid soaps acid sodium salt acid soil acid soils acid soluble acid solution acid solutions acid source acid stable acid storage acid stream acid strength acid structure acid substitution acid substitutions acid such acid supplement acid synthase acid synthesis acid tablets