Plz what does list of grievances mean

Describe the technology advancements that lead to explorers being able to sail great distances. [[ps: doesn't explain where. i am only speculating it's in europe.

How did people in the 14th century understand black death

What two different approaches did the knights of labor and the american federation of labor take in building a union organization? a) the knights of labor accepted only unskilled workers; the american federation of labor accepted only skilled workers. b) the knights of labor accepted skilled and unskilled workers; the american federation of labor accepted only skilled workers.c) the knights of labor refused to accept african american or chinese workers; the american federation of labor accepted all workers.d) the knights of labor accepted workers from a single industry; the american federation of labor accepted workers from several industries.