Fighting would make a conversation not possible because it stops the conversation from continuing and instead of talking it out like a normal conversation, it stops it from happening.

The element having valency of 1 is ~
Answer:
Copper turns green on exposure to air
Explanation:
Liquid water freezes to form ice: Physical change
Reason: Water can melt back when it becomes ice.
Copper turns green on exposure to air: Chemical change
Reason: The copper can not change back from the green state when it turns green.
12.8 mole of CO2 from the combustion
Answer:
F. Universe
Explanation:
Universe and Galaxies are two different things.