What were the advantages for the union in the civil war?

There where not many advantages, the south had good leaders but the north had more president Lincoln was a huge advantage for the north for his determination to win. The union had 20 million solders as the south only had 9 million. The union also had an industrial base, they had many rail rd. The union made there own supplies guns, cannons,est.      

More than 4 million enslaved hunan beings in the south and they touched every aspect of the regions social, political and economic life.

Ithink its c) the conditions in the factory have never been questioned by the employee.