If there are 50 grams of u-235 on day zero of radoiactive decay, how much will there be after 4.5 billion years?

b is the correct

points

explanation:

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's 3.2 on edge, i just took the test.