Concerning these two webpages...both of which are the same...

1. Which will the search engins pick up? eithor or both?
2. If both, wont that hurt me for 'duplicate' material?
3. First url is from Archive, Second url is from Catigories
4. If it can hurt, how can i turn off the and block the archives so that search engines will not index or at least not burn me for duplicate content?

Thanks, James Horan