Which of the following is true regarding functions Check all that apply

{} the vertical line test may be used to determine whether a function is one- to- one.

{} the horizontal line test may be used to determine whether a function is one- to- one.

{} a function is a relation in which each value of the input variable is paired with exactly one value of the output variable.

{} a sequence is a function whose domain is the set of real numbers