What do you know about bones?

My son came to me out of the blue to tell me about bones ....

哥哥: 妈妈, I tell you something. You know, bones are very important.
妈妈: Is it?
哥哥: Yes! It makes all our body parts hard.
妈妈: Hmmm ...
哥哥: You cannot see it but inside are all bones (offering me his arms to me to feel it). Hard, hard hor?
妈妈: Hmm ... oh, yes!
哥哥: If we don't have bones, our body will be very soft. Like a doll, floppy floppy.
妈妈: How did you know all these?
哥哥: I learn it myself.
妈妈: From where?
哥哥: The VCD you bought for me, lor.

And who said watching VCDs is not good for kids?

* Why? Why? Why? Find the answers here! *