Shivering
Explanation: shivering action is an act to warm a homoeothermic body. Sweating makes the body cool, panting don’t keep body warm and dilating blood vessels does not keep body warm instead constriction of blood vessels is the initial process to conserve body heat followed by waves of muscle contraction, which is nothing but shivering. Alteration of the set point in torpor is also not the right answer
The serotonin binds to a G-protein -coupled receptor and activates a G-subunit . This results in activation of PKA and closing of the potassium channels. This will subsequently decrease the influx of potassium ions into the cell, and lead to depolarization of the cell. This changes the membrane potential of the cell.
Aplysia are sea slugs which fall under the category of mollusks. Serotonin is a hormone which is responsible for the transfer of electrical signals from the brain to different parts. In this particular mollusk, serotonin was studied to find that it is an essential neurotransmitter that is responsible for the maintenance of synaptic plasticity in the neurons. Synaptic plasticity is the feature which is essential for the communication of neurons. This is the modification which occurs at the synapses during the transmission of synapses. Without this activity, the transmission of signals would be impossible.
Learn more about depolarization here-
brainly.com/question/8438145
#SPJ4
They begin to form about 3.8 billion years ago