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.
There are 2 cells present after mitosis 5. c. 2 chromatids in each replicated chromosome 6. In the original cell shown in model 1 during prophase, there are 4<span>replicated chromosome </span>7<span>. There are </span>4<span> single chromosome in each new cell of telophase 8.</span>
Answer: Homeostasis refers to the body’s ability to maintain a stable internal environment.
Explanation: Maintaining homeostasis requires that the body continuously monitors its internal conditions.
Hope this helped! :)
I believe the anwser you are looking for is the
Cell Membrane.
It is a substance that lets things in and out of the cell
Protons, electrons and neutrons. Hope that helped :)
