Give at least two results of too little air being in a running engine.

The answer is:

Due to little oxygen, the fuel does not burn completely and therefore only a small proportion of power of the fuel is harnessed to turn the pistons. This can even cause the engine to stall. Due to incomplete combustion, because there is more fuel than oxygen in each combustion cycle, the exhaust will be darker due to unburned carbon.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be