India comprises a dominant armor, and the geologically current Himalaya mobile belt shapes outline its northern boundary. North America and South America are independent continents, the joining isthmus being mainly the consequence of volcanism from moderately new subduction tectonics.
The Isthmus of Panama, also traditionally identified as the Isthmus of Darien (Istmo de Darién), is the thin band of land that lies flanked by the Caribbean Sea and the Pacific Ocean, connecting North and South America. It comprises the nation of Panama and the Panama Canal. Like numerous isthmuses, it is a site of great tactical worth. The isthmus is thought to have been shaped around a million years ago, unraveling the Atlantic and Pacific Oceans and instigating the formation of the Gulf Stream. This was firstly recommended in 1910 by North American paleontologist Henry Fairfield Osborn. He founded the suggestion on the fossil record of mammals in Central America. This assumption postulated a groundwork for Alfred Wegener when he projected the theory of mainland drift in 1912.
Thus, option (A) is correct.
As the linking channel between two vast landmasses, the Panamanian environment is employed with overlying fauna and flora from both North and South America. There are, for example, over 978 species of birds in the isthmus extent. The tropical climate also reassures a multitude of huge and radiantly colored species, insects, amphibians, birds, fish, and reptiles. Separated along its stretch by a mountain range, the isthmus's weather conditions are usually drizzly on the Atlantic (Caribbean) side but have a richer separation into wet and dry seasons on the Pacific side.