In English there is and apparently in Turkish too. In English, if you say America or American without any qualifiers, it means the country known as (the United States of) America. In Spanish, the word América refers to North America and South America collectively. The English speaking world regards those as two continents. To refer to both together, we say "the Americas".
Isn't there a way to refer to the United States without using simply "Amerika"?
Is there a different term for the continent? (considering that in Brazil we use the six continent model, instead of the 7 continents one, which regards North and South Americas as different continents).
Lastly... Since I saw Güney Amerika and probably the other is "Küzey Amerika ", how could I say "Central America"?
I completely understand where you're coming from, and in several places on Earth, they would agree with you. But most English (and Turkish) speaking countries use the 7-continent model. In the courses I have taken, Duo seems to always use this principle... even in Spanish! This is a huge problem because Latin America (Spanish-speaking majority) acknowledges only 6-continents.
So it's a huge debate, naturally, and I can completely understand the frustration of people who living in places that use the 6-continent model. But Duo (and frankly, the English speaking world) are unlikely to change their mind on this.
To be clear: I'm not saying you're wrong... Both views are equally correct, no matter what people argue. (Sorry if that offends anyone, but we can all be right even though we disagree! Continents are man-made divisions: we could have made ) I'm just saying that Duo will not adjust this because it is based in the United States- which uses a 7 continent model, including North America and South America, and where "America" is a country.
Definitely not fair to people elsewhere, but I'm sure we can all agree that this isn't the only way that the English-speaking majority has been making executive decisions for planet Earth, whether it's fair or not.
However, I do appreciate when people bring this up (politely, as you have done!)... To be honest, I'm from an English-speaking country, and I had no idea there was a 6-continent model until I read about it in a Duo discussion. So thank you for teaching us something that English-speaking school systems might not. :-)