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.
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Answer:
light is the independent variable, height of the plant is the dependent variable. Dependent is the effect that based on the independent.
Explanation:
lets break it down. 1) you want to know the effect of something you apply from one thing to another. Let say, if you grow your plants under the sunlight, the plants grow taller. In this case, the sunshine is the independent variable whereas the height of the plant/how tall it can grow is the dependent variable. 2)NOW, before i give the answer. The design of the question is not good for high school students. i think your teacher thinks "light" is the independent variable. 3)However, the question contains confounding variables in it because different lights might produce different effects to the height of the plants. If you want to test if plants are exposed to light grows taller than plants do not expose to light, then you should have all the lights are the same. 4) So, all the plants should be exposed to one certain light to avoid confounding. Confounding means that either red light and sunlight are both produce the same effect whereas the other colors do not help the plants to grow taller. 5)Your teacher should test one light at a time. So, if he is testing with all different colors of light, then light is the independent variable, and height of the plant is the dependent variable.
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<span>A total of four haploid cells are formed.</span>
