gravitythe natural attractive pull between objects with mass, keeping planets in orbitEinstein's general theory of relativity describes gravity as the curvature of spacetime caused by mass.NoteEinstein's general theory of relativity describes gravity as the curvature of spacetime caused by mass.Elon.io is an online learning platformWe have an entire course teaching TOEFL Academic Vocabulary grammar and vocabulary.Start learning TOEFL Academic Vocabulary now