1 What medicine is the most efficient to cure the disease? <- Missing question mark.
2 Show me where is the Russia on the map. <- "Show me where Russia is on the map." Two mistakes: it's "Russia" not "the Russia". Also the verb "is" has to be after the subject, because it's not a question ("Where is Russia?", but "Show me where Russia is."
3 How many apples are there on the table altogether ? <- Correct.