How long did it take for the human population on earth to go from two billion to six billion? less than 50 years less than 100 years less than 150 years less than 200 years

If I am correct, it took less than 50 years for the human population to sky rocket

:)

above statement is not a true statement about the open ocean because the open ocean has low levels of nutrients. most of the photosynthetic activity on earth occurs in the open ocean within the photic zone. organisms in the deep ocean are exposed to frigid temperatures and total darkness but it does not begin at the low-tide mark.