18. All organisms are mostly the same in A. the proteins they make on their ribosomes. B. how their proteins catalyze chemical reactions. C. the size of their genes. D. the molecular biology of their genes.

D.) domain, kingdom, phylum, class, order, family, genus, species

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature