North America and South America joined by ______
A) Suez Canal
B) Bering Strait
C) Strait of Gibraltar
D) Isthmus of Panama

Hint: North America and South America is joined by a narrow strip of land which lies between Carribean Sea and Pacific Ocean. The separation in fact caused the creation of Gulf Stream.

Complete answer:
 Isthmus of Panama joins North America and South America. Isthmus of Panama was known as Isthmus of Darien. It is a narrow strip of land that lies between Caribbean Sea and Pacific Ocean which links North America containing Panama and the Panama Canal. This location is obviously of great strategic value.

This was formed about 2.8 billion years ago which is believed to have separated the Atlantic and Pacific Ocean also causing the creation of the Gulf Stream. In 1915 the town of Panama was discovered near a settlement in Pacific coast and in the years 1513 Pacific Ocean was discovered. If this is described in simple words, where Panama lies today, the area used to be covered by ocean and there was a gap between North and South America.

 There were two plates beneath the surface that were colliding into each other and the pressure and heat caused by the collision led to the formation of Underwater volcanoes which glue enough to break the surface and form Islands. Over the time massive amounts of sediments peeled away and the gap between the islands were filled; this is what came to be known as Isthmus of Panama.

Thus the correct answer is option ‘D’ i.e, Isthmus of Panama.

Note: In 1881, Ferdinand de Lesseps, head of a French company, a former diplomat who developed Egypt’s Suez Canal, planned on building the Panama Canal. But due to a lot of factors like poor engineering, he failed to do so. It was only after 10 years, the canal was finally built after stopping the construction several times in the middle.