Annelids have neither an external or an internal shell. Examples of annelids are
earthworms and leeches.
A small amount of fat is an essential part of a healthy, balanced diet. Fat is a source of essential fatty acids, which the body can't make itself. Fat helps the body absorb vitamins A, D and E. These vitamins are fat-soluble, meaning they can only be absorbed with the help of fats.
-Jen
Answer:
a plant hormone which promotes leaf detachment, induces seed and bud dormancy, and inhibits germination.
Answer:
I, II, III
Explanation:
A threshold stimulus is a stimulus that is capable to produce a response in excitable tissues such as neurons and muscle fibers. At threshold potential, the outward movement of K+ and inward movement of Na+ become equal to each other. When the potential exceeds the threshold potential, more and more Na+ enter the cell to depolarize it and to allow the opening of Na+ channels. Therefore, to fire an action potential, the threshold must be exceeded.
Conduction of action potential is all or none phenomenon which means that either it occurs or it does not occur. As an impulse is passed by each successive part of an exon, it enters the refractory period during which there is no conduction of nerve impulse. It ensures the one-way conduction of impulse from the cell body to the axon terminal only.
