Practice Regents Exams with explanations.  You can do the whole exam and check your answers, or sets of questions.

These are FANTASTIC videos on almost any biology topic.  If you are struggling to understand a topic, this is the place to look to have someone explain it to you! 

Basically an online 'textbook' with videos and review questions.  This is also a great place to look to get more explanation on whatever topic you are struggling with.

If you need to do Regents review, this is a fun way to do it. 

Two Living Environment teachers created videos on the most commonly asked questions on the LE Exam.  These are things that almost always show up, and they show you how to get these questions correct. 

Most of the videos are paid, but this link will show you some of the videos that are free.