Hi, I’ve just finished my a levels and took bio, chem and PE. I found bio much easier than chem because it’s more content-based rather than calculation-based. While there is a lot of content, if you have a good system, it’s not too bad! I probably found bio the least stressful of my subjects. I recommend making notes form the textbook ahead of the lesson. This means your lesson time is free for making further notes and asking questions to make sure you understand, rather than about learning the content for the first time. After lessons, I always made a summary of my notes, and then I copied the summary into a spaced repetition app I had, which gave me a notification to review it every so often. This was I was effectively going over each lesson’s content 3x, and then reviewing it constantly with spaced repetition. Exam questions are also important, you can ask your teacher for some on the topic you’re currently doing. And also ask your teacher if you need help!