Answer:
asking about subjective matters
possibly leading to a testable hypothesis
addressing a gap in knowledge
I got soo confused about that last part. I didn't know if that was an option or something you needed to be answered.
Descriptive investigations are not repeatable because they are based only on observations made at a single point in time. The results may vary at a different time. In addition, descriptive investigations do not contain variables that may indicate cause-and-effect relationships.