Due to the geographical differences in the world, humans have evolved to adapt to their environment. For example, someone who has lived near the equator or has had descendants from near the equator would have more melanin compared to a person from the north or south. Melanin causes skin pigmentation.
While Asia is one large continent, there are different countries with different cultures and religions. For example, Buddhism is a large part of eastern Asia while Hindu is a large religion in India and surrounding countries. Islands in the pacific have built upon ancient village traditions and modernized them. Islam is large in central Asia and the middle east.
Europe is divided into 4 main parts - North Eastern Europe, The Balkans, Central Europe and Western Europe. They are mainly Christian with some Islamic groups in the Balkans and other regions. The Balkans and parts of North Eastern Europe are Christian Orthodox and Central and West Europe are mixed between Catholic and Protestant. There are also Jewish in Central Europe.
Africa’s many countries each have unique beliefs from their tribal days. They also are mainly Islamic and Christian with the different branches of the major religion taking hold of different regions of Africa. The North is Islamic but there are predominantly Christian countries near the Horn of Africa. In the south, Christianity is practiced the most.
North America is made of large countries and smaller island nations. The USA is a melting pot of different cultures with Jews, Muslims, Christians, Native Americans and other religions making up its population. Canada is also varied in culture but there are also smaller communities up north of inuits. Mexico and the island nations are also Christian due to their history.
South America has 13 countries with are all mainly Christian due to the history of them. However there are still smaller amazonian tribes and people who live in the Andes who still practice the tribal beliefs. There are also remnants of older religions as can be seen with some of the festivals and ideologies of the country
They are also mainly Christian due to the history. However, in order to honor the older beliefs there are mountains and places with their original aboriginal names like the worlds largest rock Uluru. In the Pacific Island Nations, traditional beliefs can still be observed due to the large tribal nature of these countries.