Nations usually specialize in industries where they have a
comparative advantage.
quaternary sector.
secondary sector.
primary objective.

The correct answer is comparative advantage.

The nations prefer those those type of businesses, which provide a comparative advantage as compared to the other nations present in the world. In this case, the competition decreases, as the nations are able to produce such things, which cannot be done by others. These cost for the establishment and running these industries in these nations is lower than other nations.

ability to bond woth oxygen

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do