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.
Answer:
Hello! There are numerous things that support Darwin's theory of evolution, but the most credible ones include:
*Homologous structures - structures that are similar in structure but different in function (e.g. wing of a bat and arm of a human).
*Embryology - the study of embryos
*Continental drift - some fossils of organisms that were adapted to a different environment are often found in different climates/areas they don't seem to have been adapted to.
*DNA - similarities in the genomes of certain animals are often used to compare amino acid sequences and protein production.
I hope I helped!
There are a bunch more, but I decided to leave a select few for you to write about.
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Answer:
Seed coat bursts, radicle grows downward, hypocotyls form loop above the ... (e) Plumule: It forms the future shoot.
Explanation:
Obsolete body of thought on the ordinary formation of living organisms without descent from similar organisms. Typically, the idea was that certain forms such as fleas could arise from inanimate matter such as dust, or that maggots could arise from dead flesh.
If you push a truck and push a car with the same force, the car will have more acceleration than the truck, because the car has less mass.
It is easier to push an empty shopping cart than a full one, because the full shopping cart has more mass than the empty one.
