The answer to this question would be D.) Permafrost prevents penetration of deep roots.
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Polypeptide chains undergo some modifications before they become fully functional. Some of these modifications include: proteolytic cleavage, lipidation and glycosylation. Proteolytic cleavage refers to the removal of some amino acids from a polypeptide chain by proteases in order for the protein to become active. An example of a substance that is modified through this process is insulin.
The correct answer is: prevent reception of a signal in a receiving neuron
Neurotransmitters are signal molecules or chemical messengers which transmit signals across a chemical synapse. Neurotransmitters send the signal, from one neuron (nerve cell) to another neuron, from neuron to muscle cell (motor plate), or from neuron to gland cell.
Drugs that bind to neurotransmitter’s receptor can have two effects on its action:
• Antagonists-they bind to receptor and thus prevent a neurotransmitter from binding to it
• Agonists-they bind to receptor and mimic the normal neurotransmitter (have the same effect as neurotransmitter).