Question - What are keys in React? 
          
        
        Answer - 
        
A key is a special string attribute that needs to be included when using lists of elements.
Example of a list using key -
const ids = [1,2,3,4,5];
const listElements = ids.map((id)=>{
return(
  {id}
)
})
Importance of keys -
- Keys help react identify which elements were added, changed or removed.
 - Keys should be given to array elements for providing a unique identity for each element.
 - Without keys, React does not understand the order or uniqueness of each element.
 - With keys, React has an idea of which particular element was deleted, edited, and added.
 - Keys are generally used for displaying a list of data coming from an API.