Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

How many letters are in the alphabet?

What is the Surname of Barbie Doll?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

John was piloting a plane behind a car but was never able to overtake it. Why?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

I’m orange, I wear a green hat and I sound like a parrot. What am I?