why apple logo has a bite?

To give it a sense of scale, so as to make sure it looks like an apple and not a cherry.

You might find this article interesting:

http://www.edibleapple.com/2009/04/20/the-evolution-and-history-of-the-apple-log o/

Regards.

Because iMperfection is perfection 😉

The designer's own explanation is here:

http://robjanoff.com/applelogo/