The benefit of measuring the initial rate of a reaction V 0 is that, at the beginning of a reaction:
A.
[ES] can be measured accurately.
B.
changes in [S] are negligible, so [S] can be treated as a constant.
C.
changes in K m are negligible, so K m can be treated as a constant.
E.
varying [S] has no effect on V 0 .