Doubts about nebulae and star formation

I read that nebulae are formed by stars exploding and they are also thought to be the birth place of stars. Stars explode when all the hydrogen atoms are fused into heavier elements and they are no longer able to fuse heavier atoms right ? If that's the case then the nebulae should contain...



Doubts about nebulae and star formation

Doubts about nebulae and star formation