Antigenic shift refers to the combination of two different strains of influenza, different than antigenic drift, which refers to the natural mutation of a single strain of influenza
The underlined portion above is wrong. OE given by MGMAT is as below.
"This choice uses the incorrect comparison phrase "different than"; the correct phrase is "different from." In addition, the simple comma between "influenza" and "different" provides an inadequate transition between the two parts of the sentence; the addition of a conjunction such as "and is" (e.g., "... influenza, [and is] different ...") is necessary here."
I understand the explanation. But if correct 1st problem by using "different from", i think sentence will correct as part of the sentence starting with "different from" will become adjective phrase.
Please correct.
Antigenic shift refers to the combination of two different strains ofinfluenza , different from antigenic drift, which refers to the natural mutation of a single strain of influenza