Free online courses and textbooks can be used to help supplement your knowledge and improve your scores. Use these sites to study the specific topics that you struggle with.
Open Culture Physics
AcademicEarth Physics
MIT Open Courseware Physics
Cogverse Academy Physics
Open Yale Course Physics
OpenStax Physics
Open Textbook Physics
Open Culture Biology
AcademicEarth Biology
MIT Opencourseware
UC Berkely: Biology 1 and Biology 2
OpenStax Biology
Open Textbook: Biology
Open Culture Chemistry
AcademicEarth Chemistry
MIT Open Courseware Chemistry
UC Berkely Chemistry Part 1 , Part 2 , Part 3 , and Part 4
UC Irvine Chemistry
OpenStax Chemistry
Open Textbook Chemistry