SAT Practice827e0162-2691-4a51-b3c8-11c9f57a2e06
Practice one SAT question at a time

Questions come from the Bluebook question bank.

Known as Earth’s “living skin,” biocrusts are thin layers of soil held together by surface-dwelling microorganisms such as fungi, lichens, and cyanobacteria. Fortifying soil in arid ecosystems against erosion, blank

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