observing an event as it occurs discussing results with other experts publishing the results on a webpage collecting data in an experiment
I gave my students this multiple choice question: Which of these is unique to the process of scientific investigation?

Only one answer is correct among these 4 choices:
- observing an event as it occurs
- discussing results with other experts
- publishing the results on a webpage
- collecting data in an experiment

Could you tell me which one is correct?

collecting data in an experiment