Is burning a chemical reaction or a physical change? tick one box.
chemical change physical change
and then, explain why you chose your answer.

Burning is a chemical change.

In a chemical change, chemical properties change and new products are formed. In burning, coal is obtained, and the chemical properties change of any substance, be it wood, charcoal or anything. Gas is also evolved, which shows that a chemical change has taken place. 

Thermohaline circulation and gyres

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .