Chess: The Unsounded Center

What exactly makes this region unique?

White's possession and control of d4 and e4

(i) Black is unable to use c5-e5 plus d5-f5
(ii) He stands the risk of being pushed back
by d4-d5 and e4-e5

d4-e4 therefore gives White an offensive plus
territorial advantage. If he can get in c4 and
f4, his central presence becomes intimidating:

The same is true if Black is ruler of d5-e5.
White's home ground is invaded at d4 and f4
plus c4 and e4. He may also lose ground to
d5-d4 and e5-e4.

If Black can manage c5-d5-e5-f5 his
central set-up also becomes threatening:

In either one of the above cases, the side
controlling the center usually aims to first
secure it before assaulting; the opposing one
often thrives to weaken and destroy it before

In short, an imposing center is both a boon
and a responsibility.