Determine the four most important characteristics of an effective criminal investigator.

1.  Effective Communicator

2.  Emotionally balanced

3.  Open minded

4.  Analytical Mindset

Explanation:

1. Effective Communicator: an effective criminal investigator should master the art of effective communication, as it will always come in handy and easier to relate with people during investigation or sourcing for details or information.

2. Emotionally balanced: effective criminal investigator should avoid sentiment, prejudice or personal opinion to affect his or her approach to the information available.

3. Open minded: an effective criminal investigator should be openede to different ideas and approach in tacklingoblems. In other words, s/he should be flexible to various ideas.

4. Analytical Mindset: the ability to pick up leads and recognize suspects requires looking at cases from many different angles, using a methodical or well analyzed approach.

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."