Which mineral did people in Central Africa use to make better tools 3,000 years ago? A. Iron
B. Salt
C. CoBalt
D. Limestone

I think it's A.(Iron) Based on my research,iron played a central role in many societies of early Africa. It held both spiritual and material power. Physically, Africans used iron to create tools for agriculture, utensils for everyday life, and weapons for protection and conquest. So basically the use of iron ushered in an iron age in Africa, with the expansion of agriculture, industry, trade, and political power.

La Organización de las Naciones Unidas es una agrupación de países fundada en 1945 al finalizar la Segunda Guerra Mundial por 51 países. Su importancia es la de mantener la paz y la seguridad a nivel internacional y, sobre todo, promover entre las poblaciones las relaciones de amistad y progreso social, la mejora del nivel de vida y los derechos humanos.