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All kinds - but only one family for each type of uni-potent stem cell.
Potent means powerful.
The cobra snake has a potent venom.
'Potent' means to be strong, or have the power to influence and convince. Examples:
"The potent medicine cured the sick child after a few days." OR:
"The argument the secretary gave was short and potent."
Potent means, Something strong... E.G. A potent cup of coffee is a strong cup of coffee.