Why did Spain's overseas empire begin to lose its economic viability? a. Slave rebellions threatened sugar production.
b. Its American silver mines ran out of silver.
c. Disease killed off its sugar crops.
d. Portugal challenged Spain's colonial holdings.

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.

b.

jim crow laws were enacted in northern states.

presidency should be the title

no every country is held to the same degree as others just some member countries such as the usa and germany are more economically sound so the need to show there support to all others