A:air
because the flag would on blow if it had some kind of wind
Fossils fuels are bad for the environment because it emits air pollutants that are bad. When fossil fuels are burned it causes something called Sulfur dioxide, which causes acid rain.
An animal cell has a nucleus but no cell wall.
Its has to be A that's just plain common sense
If a bacterium cannot use citrate agar will not change its color (stays green). On the other hand, if bacteria have the ability to use citrate, the medium will change its color from green to blue.
This happens because citrate agar contains pH indicator such as bromothymol blue which transforms from green to blue in alkaline conditions.
