The distribution of this quantity is inferred from the shape of a type IV isotherm in the Barrett-Joyner-Halenda method. Materials with a “controlled” value of this quantity serve as solid supports for oligo·nucleotide synthesis. When expressed in a non-SI unit, a series of 3 materials with a “type A” structure have values of this quantity equal to 3, 4, or 5, depending on whether they have potassium, sodium, or calcium ions. In a typical SI unit, whether this quantity is less than 2, between 2 and 50, or greater than 50 determines if the material (-5[1])is described with the prefix (*) “micro,” (10[1])“macro,” or “meso.” (-5[2])Beads with a fixed, (-5[1])small value (-5[1])of this quantity (-5[1])are used to separate proteins in size-exclusion (-5[1])chromatography. (-5[1])For 10 points, zeolite-based molecular sieves have values as low as 3 Angstroms (10[1])for what quantity which characterizes the holes in a material? (10[1])■END■ (10[7]0[5])