One Vs. Zero
Here's the dirt on how these objects relate to one another:
One is equal to the number of numbers less-than-or-equal-to-zero. One is the successor of zero. As a set (in the usual construction of the naturals), zero is the lone element of one. One and zero are often seen together in the pathological construction, "one divided by zero". Anything to the zeroth power equals one.
Metrics
Parity One: odd. Zero: even.
Parity One: odd. Zero: even.