Ascientist is studying the natural feeding habits of tigers.

in order to obtain the best data, which approach should the scientist use?

a. perform tests in the laboratory
b. observe tigers in the zoo
c. observe tigers in the wild
d. set up controlled experiments

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.

it has both hydrogen and oxygen