Henry Wu, InGen Geneticist and other Human creatures you control have exploit. (When a creature with exploit enters the battlefield, you may sacrifice a creature.)
Whenever a creature you control exploits a non-Human creature, draw a card. If the exploited creature had power 3 or greater, create a Treasure token.
A creature with exploit "exploits a creature" when the controller of the exploit ability sacrifices a creature as that ability resolves.
If a creature you control exploits a Human creature with power 3 or greater, Henry Wu, InGen Geneticist's last ability still won't trigger. You won't create a Treasure token.
You can sacrifice the creature with exploit if it's still on the battlefield.
You can't sacrifice more than one creature to any one exploit ability.
You choose whether to sacrifice a creature and which creature to sacrifice as the exploit ability resolves.