Approximately 80% of australians speak english. this is likely the result of the migration of
a) europeans to australia.
b) chinese speakers out of australia.
c) aboriginal speakers out of australia.
d) former prisoners from the united states.

A Europeans to Australia 
Many Europeans flocked to Australia in 1788

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen