Why do we preferably have round manhole covers and not square ones?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

What month of the year has 28 days?

Which point will the car reach to go out?

Name a key which is hardest to turn.

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

Replace the question mark with the correct number in below Picture:

Which is heavier: a ton of bricks or a ton of feathers?

Identify the 10 differences between the two given pictures.