<span>Aplysia is a marine gastropod mollusc which is an often used model organism in neuroscience, especially on the cellular biology of learning and memory. What makes them easy to work with are their giant neurons, which are one of the largest. Aplysia neurons are suitable for studies of how neurons and neural circuits control behaviours. Its defensive reflex has been studied because it is mediated by electrical synapses, which allow several neurons to fire synchronously.</span>
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The answer to your question is,
D. Adhesion
-Mabel <3
Answer - Theory
Reasoning - Your best bet and term to describe the evolution by natural selection is theory as to still scientific theory/research is still ongoing and changes can be made in a different direction.