Here is the link to the past regents examinations and their scoring key. NYSED Past Regents
CastleLearning Also has past regents exams that you have access to although not sure they have the answers provided on the spot. The self-study feature can be very handy. Make sure you select "High School" or grades 9-12 to develop a list of questions.
This wbesite provides you real time feedback on how you did with each question and gives hints. Syvum Practice Regents The other resources under the biology section go into more depth which you will not be responsible for and are more AP biology related.
Having trouble with or want more practice with Short Response Questions?
Here is a link to a pdf document of a teacher that put together some multiple choice and short response questions mixed practice... and they are seperated by topic. Greg Arnold Questions