That's what the standardized tests (SAT/ACT) are for. The questions for the tests are the same throughout the country each year. The more selective colleges not only have a minimum SAT score, but they also have a minimum Reading and Math score as well.
But what do they test? Do you have individual marks for sciences, geography, history, art etc etc?
The SAT tests reading, writing and math skills only. each section is scored separately which are then added up to give a total SAT score. Most colleges and university ask for a minimum combined SAT score. The more selective colleges not only require a minimum combined SAT score, but also have minimum reading, writing, and math scores. You can score from 600-2400. When I took the test it only went up to 1600.
The ACT is a more comprehensive test. It has 5 sections: Reading, Mathmatics, English, Writing, and Science. You can get a combined score between 1 and 36.
There are also SAT Subject Tests which test in only one subject like math, writing, foreign languages, and history. Those tests are used to test out of required core classes in college/university. There are 20 of them.
Contrary to popular belief, most colleges accept both the SAT and the ACT equally. There is a chart which correlates the SAT and ACT scores. I took both tests. I got a 1400 on the SAT and a 32 on the ACT. Because my ACT score was worth a little more than my SAT score, I submitted those scores to the colleges I was interested in after culinary school.