Aside from low birthrates and high death rates, what can cause a country's population to decline?

Aside from low birthrates and high death rates, one of the things that can cause a country's population to decline is "emigration", since this takes place when people leave the country in question.

Explanation:

People leaving

Explanation:

the aksumite empire was an ancient kingdom located in what is now northern ethiopia from the period of 100 ad to 940 ad. its capital was the city of aksum. the kingdom established itself as one of the 4 great powers at its time, along with persia, rome, and china.

the kingdom was rich in goods like gold, iron, and salt. it established strong commercial ties with the regions governed by rome, egypt, and persia (arabia). aksum was a key location in this commercial network. trade was also facilitated with the introduction of the aksumite currency.