Answer:
3)Metabotropic receptors open an ion channel through the action of a G protein
Step-by-step explanation:
Postsynaptic inhibition and excitation are similar, or much the same. Neurotransmitters are getting attached to receptors and they are opening or closing ion channels that are in the cell and since that they are similar this statement is false.
Iigand-gated ion channels are type of membrane-bound receptors so this statement is also false.
Binding neurotransmitters and metabotropic receptors can activate G-proteins. Then, the G-proteins interact with other channels or they can bind to some other protein.