Answer:
Please find the explanation below
Explanation:
Sodium (Na) and Chlorine (Cl) are two electrolytes that play important role in the absorption of water and nutrients in the small intestine. However, as mentioned in the question, the release of sodium and chlorine would lead to a loss of water in the intestines. This is because of the OSMOTIC phenomenon.
Osmosis is the movement of water molecules from a region of high concentration of water/low concentration of solute to a region of low concentration of water/high concentration of solute via a semipermeable membrane. In this case, the Na+ and Cl- ions serve as the solutes, which when released out of the intestine causes the solution in the intestines to be HYPOTONIC compared to the intestinal environment. This causes an OSMOTIC GRADIENT.
This osmotic gradient i.e. difference in concentration provokes osmotic flow of water from the intestines, which has a low solute/high water concentration, to the outside of the intestines, which has a high solute/low water concentration. Hence, water is lost from the intestine because the solute concentration becomes low when sodium and chlorine ions are released.
Flu vaccines need to be revised and changed every year because the flu virus constantly mutates. Flu viruses can change in two ways: drift or shift. Antigenic drift occurs when genes of the virus slowly change during replication until the immune system no longer recognizes it. On the other hand, antigenic shift occurs when a major change in the virus happens. This usually leads to a totally different kind of virus. This is what happened during the H1N1 scare in 2009.
DNA viruses like mumps are less prone to mutation due to the presence of DNA polymerase. RNA viruses are more prone to mutation because they undergo reverse transcription to simulate the role of DNA.
Protection and seed dispersal
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