Final answer:
Turkey and Iran are distinguished from other countries in the region by their continuous independence, as they have not been formally colonized by European powers. Turkey's unique Turkish heritage and Iran's significant Persian influence contribute to their distinct identities.
Step-by-step explanation:
The historical detail that makes Turkey and Iran different from other countries in North Africa and Southwest Asia is D) Continuous independence. Although there was a colonial presence in the Middle East and North Africa, especially after the fall of the Ottoman Empire, Turkey and Iran have a distinct history of maintaining their sovereignty. Turkey emerged as a successor state to the Ottoman Empire with a democratic government and despite various political transformations, it has never been formally colonized by a European power. On the other hand, Iran, with its rich Persian history, has been influenced by various foreign powers over time, but it has also remained an independent state, especially noteworthy for its religious state governance and calls for reform and personal freedoms.
Both countries possess unique characteristics; Turkey's Turkish heritage and language stemming from Central Asia set it apart from the primarily Arabic-speaking nations of North Africa and Southwest Asia. Iran, while majority Muslim like its regional neighbors, has a significant historical Persian influence and is a modern Islamic Republic that values its Islamic and pre-Islamic past.