What was an effect of the civil war apex

three new amendments were added to the constitution

Three new amendments were added to the US Constitution.

Explanation:

The US Constitution added in multiple amendments after the Civil War to protect the rights of African Americans.

The 13th amendment ended the institution of slavery, freeing millions of African American men and women.

The 14th amendment ensured that all individuals born on US soil were automatically US citizens. This ensured that former slaves born in the US were citizens and had all the protections/rights of other American citizens.

The 15th amendment gave African American men the right to vote.