Answer:
Ionic
Explanation:
Sodium is Metal, Oxygen is Non-metal. Non-metals and metals are automatic Ionic bonds
'The Sedimentary rock formed from years of sediments piling on top of it and being compressed.'
Answer: This is hard to do accurately, but here is my best assessment.
Explanation:
Experiment: B - describes how the experiment was done
Conclusion: A - The data support the prevailing hypothesis
Research: D - This is what we analyzed
Analysis: C - We compared the data
Answer: 
Explanation:
Electron gain enthalpy is defined as energy released on addition of electron to an isolated gaseous atom.
The amount of energy released will be maximum when the tendency to attract electrons is maximum. As flourine has atomic number of 9 and has electronic configuration of 2,7. It can readily gain 1 electron to attain stable noble gas configuration and hence liberates maximum energy.