How do scientists count a species population?
o
a. add up the individuals who leave an area or die.
o
b. add up the individuals who come into an area because of
reproduction or immigration,
o
c. add up the individuals who come into an area and subtract those
who leave the area.
o
d. add up the biodiversity in an area.

A.Add up the individuals who come into an area and subtract those who leave the area.

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."

answer; differentiation;