What is the perhaps the most profound work of science published during the latter half of the 19th century?

The most profound work of science that was established during the latter half of the 19th century is the Charles Darwin's on the Origin of Species. It was a preservation or protection of preferred races in the struggle for life most especially the evolutionary period.

the answer is use of support  

. political or economical policy that isolates a country from participating in international relationships. it has been suggested that the united states participates in isolationism because of its lack of involvement in particular wars or alliances.