B because it had bones and the others don’t
M(KNO₃)=101.1 g/mol
M(CO(NH₂)₂)=60.1 g/mol
m(N)=M(N)m(KNO₃)/M(KNO₃)
m(N)=2M(N)m(CO(NH₂)₂)/M(CO(NH₂)₂)
2m(CO(NH₂)₂)/M(CO(NH₂)₂)=m(KNO₃)/M(KNO₃)
m(CO(NH₂)₂)=M(CO(NH₂)₂)m(KNO₃)/(2M(KNO₃))
m(CO(NH₂)₂)=60.1*101.1/(2*101.1)=30.05 g
Make an observation.
Ask a question.
Form a hypothesis, or testable explanation.
Make a prediction based on the hypothesis.
Test the prediction.
Iterate: use the results to make new hypotheses or predictions. Hope this helps