A specie which accepts electrons.
Speed is a scalar quantity while velocity is a vector quantity.
It is a living document that requires frequent review about how much we have achieved and how much is left to achieve within the time frame. Hence it may be revised based on the targets and the time left.
A number of steps you can take are:
1) understand all of the concepts really well
2) try to memorize keywords These are usually the points examiner wants in your answers. If you go through the objectives in the syllabus for any chapter these words are mentioned there too. Ex: in Chemistry while dealing with a question regarding the rate of reaction, the examiner wants you to write “concentration” instead of “amount”. In Biology, writing only “sunlight” will not gain you any marks whereas “sunlight intensity” will.
3) solve as many past papers as you can. This really gets you familiarised with the keywords
4) when you get anything wrong in your answers, write it down, try to understand your mistake, and review it in spaced intervals.