Concat method does not change the main array; instead, it combines multiple arrays and returns a new array.

Double equal (==) checks only the value equality and also converts the value into the same type, whereas triple-equal (===) strictly checks value equality and also it does not convert the value into the same type. If a variable's value is same but their type is different then it will return false..

Create or insert operations are used to insert or add new documents in the collection.If there’s no collection,then it will create a new collection.

CSS position property determines the positioning of an element and also plays an important role of how the element will be displayed in the browser.