Neurotransmitters may be removed from the synaptic cleft by ____.

A) enzymatic breakdown or reuptake by presynaptic cells
B) enzymatic breakdown only
C) reuptake by presynaptic cells only
D) neutralization by antibodies
E) ionic degradation

Neurotransmitters can be removed from the synaptic cleft by enzymatic breakdown or reuptake by presynaptic cells. Enzymatic breakdown occurs when enzymes break down the neurotransmitter molecules into their individual components, while reuptake involves the presynaptic cell reabsorbing the released neurotransmitter so that it can be used again in another synaptic transmission. These are the main ways that neurotransmitters are removed from the synaptic cleft, and the other options listed (B, C, D, and E) are not accurate processes for removing neurotransmitters.