Is it correct to assume that civilization advances are only dependent on the tech tree? i.e. you must have A before you can discover B. Is it also dependent on time? On type of government? On what other civilizations are doing? On what advances I already have?
1. There was once occasion when I could research Trade. I chose to research something else (I forgot what, just call it X). Then when I have discovered X, I get to choose again what I want to research. To my surprise, Trade is not in the list anymore. But I have not learnt Trade from other civs or obtained it by conquest. Then a few more discoveries later, Trade appears again in the list of choices. Any ideas?
2. Also, are some advances dependent on time? E.g. you can't research Gunpowder before 500BC or something like that.
3. Does the number of science beakers required to discover a new advance depend solely on time? E.g. in 2000BC you need 100 beakers to get a new advance but you need 4000 in 200AD. Does it also depend on the type of advance? E.g. 100 beakers for Seafaring and 3000 for Cure for Cancer.
1. There was once occasion when I could research Trade. I chose to research something else (I forgot what, just call it X). Then when I have discovered X, I get to choose again what I want to research. To my surprise, Trade is not in the list anymore. But I have not learnt Trade from other civs or obtained it by conquest. Then a few more discoveries later, Trade appears again in the list of choices. Any ideas?
2. Also, are some advances dependent on time? E.g. you can't research Gunpowder before 500BC or something like that.
3. Does the number of science beakers required to discover a new advance depend solely on time? E.g. in 2000BC you need 100 beakers to get a new advance but you need 4000 in 200AD. Does it also depend on the type of advance? E.g. 100 beakers for Seafaring and 3000 for Cure for Cancer.