Why Are Supernova Explosions Important for Our Existence

Multiple Choice

Why are supernova explosions important for our existence?

A) They heat the interstellar medium and help keep Earth warm.
B) They liberate from the star's core the heavy elements of which we and Earth are made.
C) They destroy wandering stars that might otherwise collide with our Sun.
D) They bathe Earth in X-rays that may have helped life form.
E) They sterilized the young Earth and allowed life to originate by killing off competing bacteria.