What of the gasses is N and the flame changes it's color from Orange to blue
You should always study. you can be above your class. thats what i do.. search google for ur course. they can tell u some key points for it. u should even study what you know and want to know as well.
The answer is never because there's no electricity
(20/23) times 100 is 87%
now the answer asks for percentage ERROR
100-87 =13
so answer is C
