Anki is a free flashcard app that uses spaced repetition, which means that it tracks what you know and schedules reviews right before you're about to forget, so material actually sticks instead of fading a week after you close your notes.

For a subject as fact-heavy as Biology, that matters. Cramming the night before a meet fills short-term memory, but it won't carry over to the higher-level exams weeks later. A few minutes with Anki each day will. Anki is great for subjects requiring lots of memorization, like biology, but isn't as effective for calculation-based subjects like chemistry and physics

How to use it: first, complete the corresponding presentation to get a strong overview of the topic. Once you finish all practice problems at the end, download the Anki deck and import it to Anki. Make sure to study a little every day rather than binging once a week — the scheduling only works if you show up regularly. Trust what it tells you to review, and actually try to recall the answer before flipping the card.