How does the active compound in poison ivy protect the plant from predators?
It is a strong acid that burns the skin.
It dissolves skin cells and causes pain.
It starts an immune system response that causes a rash.
It makes the skin more sensitive to oxygen.

Question

How does the active compound in poison ivy protect the plant from predators? 
       It is a strong acid that burns the skin.
       It dissolves skin cells and causes pain.
       It starts an immune system response that causes a rash.
       It makes the skin more sensitive to oxygen.

dqswag · Answer

It starts an immune system response that causes a rash.