Why did the union become more concerned with ending slavery during the
civil war?

answer; slavery should be outlawed in the new country, was part of the initial draft of the declaration of independence, but not part of the final

the answer is: must pay taxes on profits

since it is considered as a part of your income, profits from investments is eligible for tax payment.

the tax from your investment could be influenced by how long you decided to sell it. united states promotes keeping your investment for long term period. so, the tax rate for investments that you sell in less than one year is typically higher compared to investments that you sell in more than one year period.