The proposition that heritable characteristics that provide a survival or reproductive advantage are more likely to be passed on to subsequent generations is known as:

natural selection

Explanation:

Natural selection is differential survival as well as the reproduction of the individuals because of the differences in the phenotype. It is the key mechanism of the evolution, change in heritable traits characteristic of the population over the generations.  

Charles Robert Darwin popularized term "natural selection", contrasting term with the artificial selection, which in the view is intentional, whereas the natural selection is not.

the correct answer is modern american cars are not available due to trade restrictions.

trade between cuba and the united states have serious restrictions. the u.s. imposed an economic embargo on cuba, that among other things means that modern american cars are not available due to trade restrictions.

in response to some governmental actions of the authorities from cuba, president john f. kennedy proclaimed an embargo on trade between both countries in february 1962. the trade embargo remains active until this day and was implemented directly by the departments of commerce and the department of treasury.

in president trump’s administration, there is a national security presidential memorandum that "strengthens the policy of the u. s.", affecting trade with cuba.