How does the scientist benefit society? O A. The scientist uses specialized training to direct nonscientific
thought in society.
B. The scientist uses specialized training to tell society which
problems need to be fixed.
O C. The scientist uses specialized training to force governments to act
only in ways that benefit society.
D. The scientist uses specialized training to help solve problems
faced by society.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.