Answer:
The process of synaptic vesicle exocytosis is blocked by clevage of SNARE proteins. This causes the humans and animals to become paralyzed.
The SNARE proteins can be described as a group of essential proteins that mainly play their role in the exocytosis of neurotransmitters. They are also involved in the fusion of membranes.
The toxins of botulinum are known to be one of the most potent toxins which also have the capacity to block the neurotransmitter, acetylcholine, hence causing paralysis.