Answer is hypertonic.
The ability of an extracellular solution to make water move into or out of a cell by osmosis is known as its tonicity. Tonicity is concern for all living things, especially in in organisms lacking cell wall, <em>Paramecium</em> is one such protozoan. It has specialized structures called contractile vacuoles. A contractile vacuole collects excess water from the cell and release it out, keeping the cell from lysing as it takes on water from extracellular environment which hypotonic (a lower osmolarity than the cell’s cytoplasm) as compared to hypertonic environment inside <em>Paramecium</em>.
In general, the process responsible for the growth and repair of human tissue is the healing process, which takes place in three phases.
1. inflammatory response. Injured tissues release chemicals that draw resources to the area, alert the body that damage has occurred and inhibit function to prevent further injury.
2. Repair phase. Once injured area is walled off and debris removed, construction to replace or repair injured tissue begins. New blood vessels grow in the injured area maximizing transport within tissue.
3. Remodeling phase. Construction of permanent tissue , typically strong scar tissue made from dense network of collagen fibers.
Looking at it from cell level, the process of mitosis is actually taking place during healing.
Mitosis is used for growth and repair and produces diploid cells identical to each other and to the parent cell.
New cells are needed throughout life. These are for growth and replacement of damaged or worn out tissue. The body obtains such through the process of mitosis.
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.
