The answer to an <span>action potential an all-or-none response to stimuli </span>voltage-gated ion channels open when membrane potential passes a particular level
Answer:
Cnidaria
Explanation:
Hydra, genus of invertebrate freshwater animals of the class Hydrozoa (phylum Cnidaria).
Thin coat , becaus eit protects from temperature
Answer:
<u>Breathing: </u>is the physical process of exchanging gases
<u> respiration: </u>is a chemical process that takes place at a cellular level and produces energy.
