Can someone answer this for 25 points

1. Should be I

2. O

3. O

4. I think would be I

Hope I'm right biology is confusing :P

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.