This is almost an essay-style response to a question, but that's not something to be scared about. Being prepared to write an essay response will help you structure your argument in a way that best answers the question while allowing you to demonstrate your knowledge of the topic, and so gets you the best mark possible! 16-mark questions will provide you with a statement and ask 'How far do you agree?'. First, you should provide a brief introduction to your essay: a statement about what your argument will be, to explain how you have interpreted the given statement. Then, you will need to structure your answer into paragraphs framed around the different specific points you are making. You should plan these points beforehand, and format each paragraph with the 'PEEL' (point, evidence, explain, link) structure so that you are: making it clear what your point is; providing relevant historical evidence to support this, in relation to the given statement; analysing how this agrees/disagrees with the statement; referring back to the point of the paragraph as well as the essay question, leading nicely onto your next paragraph. This will lead up to a conclusion in which you will ultimately answer how far you agree with the statement, after having analysed both sides of the argument in the preceding paragraphs. Longer answers are not something to worry about, but something to look forward to as a way of exploring how you can apply what you have learned to REAL historical questions!
See Also
Why Studying History is Important (and Why It's Fun) | FrogTutoringThe social history: Our patients are more than their diseasesHow to Write an Essay in 3 Hours - An Ultimate GuideHow do you answer a History essay question in the exam?