Question
according to the scheme for sedimentary rock identification, which characteristic determines whether a rock is classified as a shale, a siltstone, a
sanostone, or a conglomerate?

According to the scheme for Sedimentary Rock Identification, the particle size of the sediments within the rock characteristic determines whether a rock is classified as a shale, a siltstone, a  sanostone, or a conglomerate.

Explanation:

The given four types of rocks i.e. conglomerate, siltstone, sandstone and shale are the classic type of Sedimentary rocks. These rocks have different particle sizes of sediments present in them, which gives a particular characteristic to their structure.  

Conglomerate is the most coarse grained rock with size of particles 64 mm to >256 mm, and having rounded grains.  Breccia or siltstone is finer, with particle size from 2 mm to 64 mm, and angular grains.  Sandstone are much finer with grains ranging in size from 2 mm to 1/16 mm.  Shale are having the finest grains ranging in size less than 1/16 mm.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein