Thomas malthus viewed the 18th century world population growth rate

Malthus was a Demographer that viewed the world population growth rate as unsustainable.

Malthus believed that the world's growth rate was susceptible to what is now known as the Malthusian trap, that is, that food production will be unable to keep up with growth rates. Eventually, the lower classes will die off due to famine.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."

could you show the options for the answers? : )