Homomorphism from Integers into Ring with Unity/Examples/Characteristic 2

Example of Use of Homomorphism from Integers into Ring with Unity
Let $\struct {R, +, \circ}$ be a ring with unity whose zero is $0_R$ and whose unity is $1_R$.

Let the characteristic of $R$ be $2$.

Then:
 * $\forall a \in R: 2 \cdot a = 0$

or equivalently:
 * $\forall a \in R: a = -a$