Read this excerpt from "Why Are They Called Black Holes?" After many millions or billions of years, the star runs out of hydrogen and energy. Then the star "dies" and collapses into a dense little ball with tons of gravity. Albert Einstein’s theory of relativity predicted that black holes would have to exist if a dead star had enough gravity. Using Einstein's theory, astronomers calculated that if a star more than three times as heavy as our sun died, the force of gravity pulling matter in could overwhelm any other force pushing matter out.

In this excerpt, the author makes a connection between a scientific theory and

the calculations that scientists make.
the beginning of a star's existence.
the idea that all things live and die.
the question of why gravity exists.

explanation:

crosscutting concepts have application across all domains of science. as such, they are a way of linking the different domains of science. they include patterns; cause and effect; scale, proportion, and quantity; systems and system models; energy and matter; structure and function; and stability and change.

mechanics (greek   is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. the scientific discipline has its origins in ancient greece with the writings of aristotle and archimedes[1][2][3] (see history of classical mechanics and timeline of classical mechanics). during the early modern period, scientists such as galileo, kepler, and newton laid the foundation for what is now known as classical mechanics. it is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. it can also be defined as a branch of science which deals with the motion of and forces on objects. the field is yet less widely understood in terms of quantum theory.

explanation: