Action potentials are certainly a key to understand neuronal signaling, and to this day, neuroscientists are still developing specific models to try decipher how much information a bunch of neuronal spikes has to inform in distinct neurons.
Interestingly, throughout evolution action potentials have proven to be a very efficient mechanism of communication, and their most studied and most important attribute has been proved to be frequency, which is a property that depends on the source only, ie it does not change until you reach your destination. So, the right answer is Letter C.
the major difference is that protists are eukaryotes while bacteria and archea are both prokaryotes. this means that prokaryotes do not have a nucleus, and contain circular DNA.
