Are system calls in c language only????

Hi friends,
I have three questions.

1)      What are system calls?

2)      Is it necessary that system calls be in c language (in unix operating system)?

 
 
3)      Importance of c language when programming in unix environment???

Looking forward to your wonderful replies!

Thanks in advance!

This sounds like homework.

I agree.

Also, the questions are more appropriate for a Google search and a forum question.

(Closed)