Answer:
when and because
Step-by-step explanation:
When this type of ultra-massive star runs out of fuel, it goes through an initial WHOOOOOSH! of collapse. However, because its enormous mass generates such tremendous gravitation, there's no CRASH! of a rebound or BOOM! that blasts gases out into a supernova. Instead, the matter just keeps on whooshing inward, directly forming a black hole.
—A Black Hole Is NOT a Hole,
Carolyn Cinami DeCristofano