I’m glad to read the comments on Apologia biology. However I don’t share the positive sentiments on the updates. Yes, update the science but this book has taken biology to an extreme. Level. Chapter 4 has 72 definitions! There is no way to remember all of these definitions. It seems more like a college biology. Some of the terms and science is extreme for a high school student who may not even go into science. We only watch the videos, do all the work in notebook. We have found she does a better job of talking and showing the process in sequence than all of it on a page in the info graph. They are wonderful but the book bounces around in the first 6 chapters. You go from microscope, chemistry, biomes and animals to extreme cell discussions that is very involved for high school. The amount of definitions per chapter is overwhelming. The videos should not take the place of reading the book but they are much more understandable and she has added information at times that is helpful and not in the book. I do not have a 2nd addition in front of me and when we did it 10 years ago I just don’t remember it being this difficult. We are just going to plow through it. Really concerned about chemistry now, I bought the whole set already.