3 weeks is a good amount of time you are not cooked at all imo. Just start now, make good use of your time and you could get way more than 60%. Good luck
BTW biotic factors are components of an ecosystem that are living (plants, animals) and abiotic factors are components of an ecosystem that are non-living (temperature, soil). Make sure you memorise diagrams too, I remember having to label and draw diagrams and losing so many marks because I barely remembered any
good luck once again!