Answer:Karl Schwarzschild uses Einstein’s ideas about space bending to conclude that black holes are possible
Explanation: we know this because its states it in the paragraph, "Einstein's idea of gravity had big consequences. It helped explain some observations that Newton's idea didn't account for. It also opened our minds to amazing new possibilities. For example, taking his cue from Einstein's idea that space bends, scientist Karl Schwarzschild began to think about what would happen if a place in space were extremely distorted. His answer: light would follow the hyper-bent space, never to turn away from it. This was the first prediction of a black hole."