I could be wrong I’m not very smart but I think it’s b
Its A, blood circulates the hormones
Answer:
The meaningful differences between organisms in a population are genetic. Variations in the genome of members of a population arise through mutation. Occasionally, a mutation occurs in an individual that is beneficial, that helps that organism be better able to survive and repoduce in its current environment.
I think Autorhythmic fibers are fibers that are self excitable or on their own for example some cardiac muscle. They repeatedly generate action potentials that trigger heart contractions.They continue to stimulate a heart to beat even when it is removed from the body. In comparison to contractile fibers, autorhythmic fibers are self excitable and do not require nervous system stimulation to trigger contractions. Contractile fibers have stable resting membrane potentials of -90mV, when a contractile fibers reaches threshold by action potential, the voltage gated fast sodium ions channels will open.
