2h2 +o2 = 2h2o balance equation with 5 oxygen

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6

Chromosome 17 is made of over million base pairs.

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?