1. Where could scientists look to observe a black hole?
- **The center of the Milky Way.**
2. What is the main challenge astronomers face when trying to directly detect black holes?
- **Black holes trap all light.**
3. Which of these characteristics of a star make it most likely to become a black hole? Select the two correct answers.
- **Its mass is greater than 20 times the mass of the sun.**
- **It is dying.**