Google because they put their ads up first so you click on them more often
True, 9 states had to approve :)
I believe that would be B. Metal weapons and armor
Hope it helps!
1840s
Factory-made agricultural machinery increases farmers' need for cash and encourages commercial farming
1841
Practical grain drill patented
1842
First grain elevator, Buffalo, NY
1843
Sir John Lawes founded the commercial fertilizer industry by developing a process for making superphosphate
1844
Practical mowing machine patented
1847
Irrigation begun in Utah
1849
Mixed chemical fertilizers sold commercially