Define the "work principle" for real machines:

The work accomplished by a machine will always be less than the work needed to operate the machine.
The work accomplished by a machine will always be greater than the work input required to operate the machine.
The work required to operate a machine is equal to the work which it will perform (output).

gas

explanation:

smoke is the matter of a gas

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.

i think its 100

i hope this !

(b) which contains higher levels of vitamin b, oranges or spinach?

explanation:

you can eliminate a, c, and d because they are questions based on opinions.