How was the migration of the bantu people supported by there use of metal-working technology

D.the role of religion has steadily declined in recent years.pl give me  branliest

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion

The answer is winds.