What is the name of the Swift language feature that Objective-C Blocks are translated into?

Which one creates a dictionary with a key type of Integer and value of String?

Which of these is an appropriate syntax for dispatching a heavy operation to a background thread?

What is the name of the deinitializer in a Class declaration?

Which of these is an appropriate syntax for declaring a function that takes an argument of a generic type?

Which of these is not a valid property declaration in Swift?

What is the type of this function? func add(a: Int, b: Int) -> Int { return a+b }

What is the value of y? var x: Int? let y = x ?? 5

What is the value of test in this code? var test = 1 == 1

What is the value of y? let x = ["1", "2"].dropFirst() let y = x[0]

What is this code an example of? let val = 5; print("value is: \(val)")