Final answer:
Relation and function are concepts in mathematics that describe the relationship between elements of two sets. A relation is a set of ordered pairs where each input has a corresponding output, while a function is a special type of relation where every input has a unique output.
Step-by-step explanation:
Relation and function are concepts in mathematics that describe the relationship between elements of two sets. A relation is a set of ordered pairs where each input has a corresponding output, while a function is a special type of relation where every input has a unique output.
In other words, for option A, if every input in the relation has a unique output, then it is a function. On the other hand, if there are multiple inputs that have the same output, then it is not a function (option B).
Inverse exists for every element (option C) refers to the concept of inverse functions, where each element in the function has a corresponding inverse element. If this is true, then it is a function. However, if there is no inverse for any element in the function, then it is not a function (option D).