My two classes this semester are about as different as they can be. The early morning class jabbers away, and is totally engaged in the discussion, making me feel like a brilliant teacher. The afternoon class sits there looking puzzled at almost everything, yawns, and makes frequent bathroom runs. Same material, different students. It always stuns me.
Judging from the writing samples, there are a number of students who have trouble with reading in the afternoon class. That may account for some of it.