According to the model of personality development, individuals at different ages can experience the same emotional and peronality changes because they have shared common occurences in their lives

did mary wollstonecraft believe was a natural ingredient for women’s happiness?

so you should go with

a. strong

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."