Answer:
government agencies is the first thing that comes to mind
Answer:
groups of participants differing in age at the same point in time
Explanation:
Cross-sectional design: This is a type of observational study design. In this study, the investigator calculate the exposures and the outcome in study participants at the same time.
The research involves different groups of people who have different variables of interest but consists of other characteristics, for example, educational background, socioeconomic status, and ethnicity.
The sun. If that's what you're asking.
