While teaching a nursing student, a registered nurse says "this is a study in which the investigator controls the study variable and randomly assigns subjects to different conditions to test the variable." which type of research is the above statement?

you so !

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.

answer; (b) knowledge based summaries of our beliefs and feeling about the self in particular domains;