Precizeaza trei factori care au condus la explozia demografica a populatiei terrei in secolul XIX-lea

Ithink the correct answer is a

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 time of day would be around 3: 00