The diagram below compares the amounts of common elements found in the human body
Carbon
Calcium
Other
Hydrogen
Which element is the label X most likely to represent?
A. Oxygen
B. Nitrogen
C. Phosphorus
D. Sodium

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.