Which matters more: GPA, or grades of individual classes?

Colleges get transcripts. Therefore, they can see both GPA and individual grades for any given class. So which matters more? An example for my question would be if I got a C and B- in a language class and history, but As and A-s in other classes which are math and science classes, and I'm applying to the college for science stuff. Which matters more here, the low GPA or will they consider the fact that I did well in science and math?