This is the free error check. Twelve questions, about fifteen minutes, and at the end it names the line you cross most often across these twelve and hands you the fix.
This is not a score predictor and it is not timed. Every question is engineered so that the wrong answer you choose reveals something. Answer the way you actually would, not the way you think you should.
All twelve passages were written for this error check. None have appeared on an MCAT.
Your CARS profile
These are three of twelve checks. The book is the whole set: the method, the worked examples, and the charting system that turns your own wrong answers into the only study document written specifically about you.
Nothing else, and no more than a few emails a year.