Answer:
<em>Your</em><em> </em><em>Answer</em><em> </em><em>is</em><em> </em><em>Option</em><em> </em><em>A</em><em> </em><em>that</em><em> </em><em>is</em><em> </em><em>Gas</em><em>.</em>
Answer:
sorry please can you snap the diagram ...the question is not clear to my understanding
It is for safety if you come to a sudden stop like newtons law say if an object is in motion it stays in motion until a force stops it if the bike suddenly stopped then you would fly off because you wold still be going. and the gear helps protect you.
Oxygen for complete combustion