Why is it difficult to determine which countries belong to Europe and which belong to Southwest Asia

Countries like Turkey and Russia span both Europe and Asia, and countries like: Ukraine, Belarus, Latvia, Lithuania, Estonia, Moldova, Kyrgyzstan, Uzbekistan, Tajikistan, Turkmenistan, Georgia, Azerbaijan, Armenia, and Kazakhstan comprise the former Union of Soviet Socialist Republics (U.S.S.R./Soviet Union; Russia effective December 26, 1991), which as a whole spanned the continents of Europe (to the west; eastern Europe) and Asia (to the east; western Asia).  

The following independent republics from those listed above that are located in Europe include: Ukraine, Belarus, Latvia, Lithuania, Estonia, and Moldova.

The following independent republics from those listed above that are located in Asia include: Kazakhstan, Turkmenistan, Kyrgyzstan, Azerbaijan, Tajikistan, Uzbekistan, Armenia, and Georgia.  

In general: bodies of water (including oceans, seas, and bays) serving as separations (not borders) between two or more countries, in turn separate one continent from another on a world map.    

seismic wave -

an elastic wave in the earth produced by an earthquake or other means.

explanation:

i only have few minutes according to the map above, which shows religious cultural regions, what two religions are most commonly practiced in africa? a. christianity and buddhism b. buddhism and hinduism c. islam and christianity d. hinduism and islam