What event sparked war between the U. S. and Spain?

"United States declared war on Spain following the sinking of the Battleship Maine in Havana harbor on February 15, 1898. The war ended with the signing of the Treaty of Paris on December 10, 1898."

the answer is a. the harappan civilisation is also called the indus valley civilisation, this is because they built their cities along the indus river. the reason behind this location can be found in the rest of the "old world" civilisations like mesopotamia or egypt, the first built their cities along the rivers tigris and euphrates, the second along the nil; : their respective civilisations thrived because the overflowing of their respective rivers produced favorable conditions for agriculture, their main support.