They are two divers subjects so there is no real problems with studying both at once.. With the exception...
Be sure to finish the last lesson exam in Biology as the last exam you do in the semester - in other words make sure you complete the Accounting before you complete the Biology.
The reason for tis is computer logic. Each night a program runs to see which students have completed all of their coursework so that their proctor exams can be automatically sent out. This is based on doing the work as it is assigned on your My Course page. If you have skipped or not completed a lesson in a previous subject by the time you fully complete the last lesson in Biology, then your name never makes it to the list to have your proctor exams sent out. You will end up waiting and waiting wondering when the proctor will receive the exams and then have to telephone in the meantime wasting time because you will have to telephone and tell the Proctor Dept. to send out the exams.
Therefore, make sure you complete the Accounting before you complete the Biology.