Final answer:
Questions enabling respondents to freely express themselves are called open-ended questions, allowing for the collection of qualitative data.
Step-by-step explanation:
Questions that allow respondents to express themselves as they choose are called open-ended questions. These types of questions do not limit the respondent to predefined choices, unlike yes-no, multiple-choice, or Likert-type scale questions which are more structured and collect quantitative data. Open-ended questions allow for more in-depth, personal responses that provide qualitative data, revealing insights into respondents' beliefs, values, and reasons behind their opinions.