Determine whether the description applies to landfills incinerators or both

answer; ///i believe the answer your looking for is (ribosomes);

answer; ///(b) it is composed of four protein chains and four heme groups;

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides