Question

which method of gathering data will be most effective in learning how diet and fitness choices affect long - term health? an experiment an observational study a sample survey a census

Explanation:

An observational study is best as it can track participants over long - term without the ethical and practical issues of controlling diet and fitness in an experiment. A sample survey and census are more about collecting general information rather than studying cause - effect relationships over time.

Answer:

B. an observational study