Earth Science
Many massive stars end their life cycles as black holes. Why do astronomers not believe the sun will end its life cycle as a black hole?
1. It is not massive enough.
2. It is much too hot.
3. It is much too hot.
4. It is not a binary star.
Which accurately describes coral reefs? Select the three correct answers.(2 points)
1. Coral reefs often are located in nutrient-poor waters.
2. Coral reef ecosystems have low biodiversity.
3. Coral reef ecosystems are among the most biodiverse on Earth.
4. Coral reefs are sturdy structures that can exist for thousands of years.
5. Coral reefs are delicate structures that usually exist for less than 10 years.
6. Coral reefs often are located in nutrient-rich waters.