Answer:
reaction 1 and reaction 4 both are decomposition reactions
while reaction 2 is double displacement reaction and reaction 3 and 5 are combination reactions
C. Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed. ( I put A & it was not the correct answer, the answer was C )
Answer: 
Explanation:
A single displacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.

Synthesis reaction is defined as the reaction where substances combine in their elemental state to form a single compound.
Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.

Combustion is a type of chemical reaction in which hydrocarbons burn in the presence of oxygen to form carbon dioxide and water along with heat.

Answer:
B
Explanation:
"I think my bike is making a scraping noise because the bearings are not lubricated."