<p>wat are the differences between them and who should take what?</p>
<p>First off, the USMLE is something you take after you go to med school. It's the US Medical Licensing Exam. If you're 18, you're not going to need to worry about that for a long while. ;)</p>
<p>The GRE, the GMAT, the MCAT, and I'm going to add the LCAT in here because it's another common graduate-level aptitude test, all are like the SATs for grad school, and you'll take one of the four depending upon where you're headed after college.</p>
<p>The GRE is what you'll take if you're going to graduate school in liberal arts, science, engineering, and fine arts (occasionally, for some branches, and depending upon the program), and any other academic fields that I may have forgotten. It's much like the old SAT, but includes an analytical writing portion. There are also GRE subject tests that may be taken in addition to the general GRE, which may be required by some graduate programs.</p>
<p>The GMAT is the entrance exam for some academic graduate programs, but is generally used as the entrance exam for business school. It includes a logic section as well as math and some verbal skills.</p>
<p>The MCAT is the medical school entrance examination. It includes a lot of science, heavy in biology and chemistry. The LSAT is the law school entrance examination, and is much like the GMAT. Many pre-law and pre-med students take prep courses in order to boost their grades on these two courses, because admission to med school and law school is highly competetive, and the tests count for a generous part of the admissions process.</p>
<p>Hopefully this helps you out!</p>