How does a star become a Type I &Type II Supernova

I need help for my astronomy class.

How do you think a star becomes a Type II supernova? …a Type I supernova? Can you think of any other way a star could become a supernova?

Thanks a bunch!

Type I supernovae are caused by small dense stars (whose 1 tsp. of matter would weigh tons) pull on their nearby companion star. MOST stars in our galaxy are binary stars (2 stars orbiting around each other), and when one of these burns up most of its fuel, if its 'normal' or average size, it will turn into a superdense neutron star. Because its gravity is so strong, it can pull material off the companion star until it pulls enough material (fuel) that is now added to its already massive size, causing it to explode. Type I novae are important because they always explode when the smaller star reaches a critical point, meaning that every Type I explosion is the same brightness. This is important because they use the apparent brightness to measure the distance to the nova.

Type II can be a variety of brightness'. They are usually stars around 5-15 times larger than our own sun, who when they run out of fuel, collapse (within a second!) and when this happens, it rebounds and the shockwave blows out the outer layers of the star. This also makes all of the elements in the Universe heavier than Iron, much like a Type I does, also. If you have anything heavier than Iron, it came from a supernova.