Prior to the arrival of a signal from a presynaptic input, the post-synaptic membrane is polar with a greater relative charge in the ecf.

Answer;

-Positive charge

Prior to the arrival of a signal from a presynaptic input, the post-synaptic membrane is polar with a greater relative positive charge to the ECF

Explanation;

-Neurons talk to each other across synapses. In somatic neurons, an action potential arrives at the synapse causing synaptic vesicles to fuse with the presynaptic membrane. The pre-synaptic membrane releases acetyl choline via exocytosis into the extracellular of the synaptic cleft.

-The ACh diffuses across the cleft and binds to the ligand-regulated sodium channels. Activated sodium channels allow a rapid diffusion down its electrochemical gradient towards the ICF. The movement of positive charges to the ICT causes the relative charge across the membrane to become positive on the inner surface.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?