Selena has a garden, and she wants to improve the soil so that her plants can grow better. She reads that compost can help improve the soil by adding nutrients to it. Compost is material made from decomposed food scraps, leaves, and grass clippings. Selena plans to make a compost bin so that she can start putting her food scraps and yard waste in it. She reads about several different ways to make compost bins. What would be the best criterion for a successful compost bin design?

i have to go with a for this one

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; formal diagnosis (vera wand formal dress);