Answer: C.
React with gases in the air.
9=a 10=b 11=f 12=c 13=d 14=e
In a COMBINATION reaction, two or more elements or compounds form one product. Combination reaction is sometimes also refer to as synthesis reaction, it is a type of reaction in which a single new product is formed by the combination of two or more elements. The reaction is typically represented by:
X + Y = XY.
It is a wedge as when it cuts it separates the two sides of what ever you are cutting just like a wedge <span />
