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.
The body needs calcium and phosphorous because phosphorus works with calcium to help build bones
The answer would be C, as many streams/rivers carry plant seeds, dispersing them. If there was a drought, these seeds wouldn't be able to float on the stream and disperse.
Microorganisms that live in severe habitats, such as very
hot, acidic, or salty environments are called extremophiles, which are
bacteria, archaea and eukaryotes. They are the most successful organisms
because they can adapt in any environment. They can live in oceans, rivers,
soil, and even inside a human’s body.
