Two developed countries have market economies with similar gross domestic products. however, one is ranked lower than the other on the united nations human development index. what might contribute to this low ranking?

Differences in life expectancy and education indexes, as well as differences on national income per capita.

Explanation:

The Human Development Index is a composite index aimed to measure people's quality of life accross countries based not only on economic growth, but taking into account other key dimensions of human development. HDI offers a more complete analysis than those based solely on GDP.

HDI is the geometric mean of normalized indices of three dimensions: 1) health (measured by life expectancy at birth), 2) education (measured by mean of years of schoooling for adults) and 3) standard of living (measured by gross national income per capita)

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."