SAT Practice06094015-954f-4609-9640-c794948f54c0
Practice one SAT question at a time

Questions come from the Bluebook question bank.

The intense pressure found in the deep ocean can affect the structure of proteins in fish’s cells, distorting the proteins’ shape. The chemical trimethylamine N-oxide (TMAO) counters this effect, ensuring that proteins retain their original blank is found in high concentrations in the cells of the deepest-dwelling fish.

Which choice completes the text so that it conforms to the conventions of Standard English?