Corrected a typo (take --> tag)

21_Day_DOM/21_day_dom.md

@@ -74,7 +74,7 @@ We can access already created element or elements using JavaScript. To access or
 
 #### Getting elements by tag name
 
-**_getElementsByTagName()_**:takes a take name as a string parameter and this method returns an HTMLCollection object. An HTMLCollection is an array like object of HTML elements. The length property provides the size of the collection. Whenever we use this method we access the individual elements using index or after loop through each individual items. An HTMLCollection does not support all array methods therefore we should use regular for loop instead of forEach.
+**_getElementsByTagName()_**:takes a tag name as a string parameter and this method returns an HTMLCollection object. An HTMLCollection is an array like object of HTML elements. The length property provides the size of the collection. Whenever we use this method we access the individual elements using index or after loop through each individual items. An HTMLCollection does not support all array methods therefore we should use regular for loop instead of forEach.
 
 ```js
 // syntax