Answer:
Environment: They must be supplied and used in ways that have minimal safety and environmental stewardship have advanced safety regulations and practices, promulgated rules for reducing VOC emissions from oil and gas production and ... disposal protocols are similarly reducing negative impacts to air and water.
Explanation:
Answer: Event 1 is an example of a physical change and Event 2 is an example of a chemical change.
Explanation: Physical change is one in which there is no change in chemical composition of the substance. There is only a change in phase change.
Chemical change is a change in which there is a change in chemical composition and there might or might not be a phase change.
On Boiling, the water molecules remain bonded in the same form and only covert from liquid to gaseous form, thus is a physical change.
On Rusting of iron nail, the iron changes to iron oxide by combining with oxygen, there is a rearrangement of atoms and thus is a chemical change.

Answer:
B is the answer because it doesn't matches the num of valence electrons