Interesting question inviting you to compare, contrast and evaluate. Consider what the question is asking you to do - ultimately it wants you to evaluate how 'democratic' the two German constitutions were - it would therefore be helpful to establish briefly what a democratic constitution would look like. In simple terms, this would include popular participation in politics i.e. universal suffrage and limited authoritarian aspects such as overt control by a leader. By establishing what a democratic constitution looks like, you would then be able to go on to discuss whether or not the Weimar constitution or the Bismarckian constitution was, or was not, democratic and how they compare to one another. I think the ideal way to answer this question would not be to list all the aspects of the Bismarckian constitution and then all the aspects of the Weimar constitution. Consider three or four major aspects of each constitution and then consider whether they show continuity with one another. Things to consider could include: the powers granted to the Kaiser/President, the power the chancellor and ministers, the power of the upper and lower house, and the rights of the German citizens.