In React, each component must have a render() function. It returns a single React element, which is, in fact, the representation of the native DOM component.
When there is a need for more than one HTML element to be rendered, we group them in one enclosing tag, which can be,or some other tag. There is a need for the render() function to return the same result each time it is invoked i.e. it needs to be kept pure.