The answer is 30 cm cubed
Liberia was formed by freed slaves from America. It was formerly a colony of the US but declared independence in 1847. The capital, Monrovia, is named after US president James Monroe. Other than Washington DC, it is the only capital city named after a US president.
The correct answer is (D.) Romans
The walls are thought to have been a symbolic show of authority, designed to preserve the privacy of royal families and set them apart from and above commoners. It is also important to note that the walls surrounded and later adjoined huts made of daga (mud and thatch), linked with them to form a series of courtyards.