Nick's teacher explained that there are certain objects that most likely exist at the center of every galaxy. These objects are so dense that their gravitational fields suck everything in, including light. They form when a galaxy or star collapses under the pull of its own gravity. Nick knows that these objects are called
A.
black holes.
B.
blue giants.
C.
nebulae.
D.
quasars.
A. black holes.
The correct answer is A. black holes.
The objects that Nick's teacher described, which are so dense that they have gravitational fields that suck everything in, including light, are called black holes. To arrive at this answer, Nick can use the information provided in the explanation:
1. Black holes are objects that exist at the center of every galaxy and are formed when a galaxy or star collapses under the pull of its own gravity.
2. These objects are extremely dense, causing their gravitational fields to be so strong that nothing can escape, including light.
3. The other options, blue giants, nebulae, and quasars, do not match the description of objects with such intense gravitational fields that they consume everything, including light.
Therefore, the correct answer is A. black holes.