The neuron releases chemical messengers. Otherwise, there would be no 'signal transduction' in the postsynaptic cell. So, your answer is B.
Genetic variation is advantageous because it enables some individuals and, therefore, a population, to survive despite a changing environment.
Answer:
How Does the Immune System Work?
Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection. ...
Adaptive immunity: Adaptive (or active) immunity develops throughout our lives. ...
Passive immunity: Passive immunity is "borrowed" from another source and it lasts for a short time.
