Answer:
D: Carbon
Explanation:
The periodic table lists all the known elements. When looking at it, the only choice you will find is carbon. Therefore, carbon is the element.
Carbon is also by itself, just C.
Water is H2O, which is a molecule due to the 2 different elements.
Carbon Dioxide is CO2, which is a molecule due to the 2 different elements.
Air is just a mixture of different gas molecules, so therefore it is not an element.
ANSWER
Power stroke
EXPLANATION
At the power stroke stage, the piston is forced to move down by the expanding gases as both intake valve and exhaust valve are closed.
A spark from the spark plug contributes to ignition of the compressed fuel air mixture to released energy to perform work.
Fluorine needs one electron to fill its orbital shell. It needs 8 valence electrons