Does "it" refer to "that makes natural selection succeed as a solution to the problem of improb..."?

Context:

What is it that makes natural selection succeed as a solution to
the problem of improbability, where chance and design both fail at
the starting gate? The answer is that natural selection is a cumula-
tive process, which breaks the problem of improbability up into
small pieces. Each of the small pieces is slightly improbable, but not
prohibitively so. When large numbers of these slightly improbable
events are stacked up in series, the end product of the accumulation
is very very improbable indeed, improbable enough to be far
beyond the reach of chance. It is these end products that form the
subjects of the creationist's wearisomely recycled argument. The
creationist completely misses the point, because he (women should
for once not mind being excluded by the pronoun) insists on treat-
ing the genesis of statistical improbability as a single, one-off event.
He doesn't understand the power of accumulation.