Chaiken (1987) and other proponents of the heuristic-systematic model of persuasion assert that emotions often signal us as to our true attitudes. By this they mean that .

Emotions often tell our feelings

Explanation:

The heuristic- systematic model is a persuasion theory, it suggests that attitudes change in two ways: Systematically and heuristically. Systematic processing is when the people carefully think about the information before forming an opinion to decide validity of the information.  While the heuristic technique is a simple way  to discover, learn and solve problem employing a practical method which is not guaranteed to be perfect or optimal  but is sufficient for the immediate goals.  

This theory state that attitude are often formed in a much simple manner and this simple form of attitude judgement is called heuristic processing. It involves use of heuristics to decide what a persons attitude should be.

This model had a great impact on the field of consumer behaviour and health behaviour.  It includes trial and error, guesstimates or common sense.  

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."