Generally, biology comes in three levels in high school: general biology, honors biology, and AP biology. They vary on how difficult the presented material is.
General biology is, by far, the easiest. The course is meant for those that either can’t handle the challenge or do not want the challenge. There will be homework (the amount depends on the teacher), but the level is not too difficult. General biology teaches you biology on a simpler level, eliminating the many details that come with the various units (i.e. protein synthesis, cellular respiration, etc.).
Honors biology is the intermediate level. The course is meant for those that want more of a challenge, as it provides a more in-depth look into the various units. There will generally be more homework than in general biology, and the level of comprehension will be more difficult.
AP biology is, by far, the most difficult level. An AP class is always a top-notch class in terms of difficulty, as AP stands for Advanced Placement. The point of an AP class is to prepare you for the AP test, which shows colleges how well you have mastered the difficult class. The course provides a very in-depth look into many areas of biology. This class is often taken after either general or honors biology (depending on the school), and thus, the units are usually further in-depth on the ones that have been discussed in previous classes or are completely new units (but still very in-depth).
Overall, AP biology is not for everyone. Because either general and honors biology are usually taken first, it is best to determine how you did in that class. If you did average in a general biology class, AP biology probably isn’t for you. If you did excellent in a general biology class or fairly well in an honors biology class, AP biology may be for you. If you did well or excellent in an honors biology class (high test scores, high grade, etc.), AP biology is definitely an option for you.