diff --git a/index.html b/index.html
index b865f3b..32ba30a 100644
--- a/index.html
+++ b/index.html
@@ -1267,7 +1267,8 @@ <h4>Exercise 11: Use map() and concatAll() to project and flatten the movieLists
 						return video.id;
 					  });
 				  }).
-				  concatAll();
+				  concatAll(); /*My browser throws error (Uncaught TypeError: movieLists.map(...).concatAll is not a function) here
+				  Could you please explain this*/ 
 
 			}
 		</pre>