Evolution Center without displayed level
Evolution Center is a 4x4 building that allows the player to increase the level their mutants can achieve. Once their mutants reach the maximum level of their Evolution Center, mutants cannot keep leveling up until they upgrade it.
Upgrades
Upgrading the player's Evolution Center can be done with 
or 
. The more they level it, the higher the level their mutants can achieve.
The first few upgrades are fairly cheap, but they start getting more expensive as they upgrade it further, up to a limit of 900 per level, or an increasing amount of (the cost tends to rise by 3,000,000 for each level).
It allows their mutants to upgrade their attacks at rate level: 5, 10, 15, 20, 25, ?
and abilities (e.g. stronger Boost, Retaliate, Drain Life, Curse, Wound and Shield).