When a neurotransmitter released from the pre-synaptic neuron binds to a on the post-synaptic neuron, that neuron depolarizes and fires.
a. enzyme-linked receptor
b. nuclear receptor
c. voltage-gated ion channel
d. ligand-gated ion channel
e. g-protein coupled receptor

d. ligand-gated ion channel

Explanation:

When a neurotransmitter released from the pre-synaptic neuron binds to a ligand-gated ion channel on the post-synaptic neuron, that neuron depolarizes and fires.

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the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: