The reason why one case of influenza does not confer lifelong immunity is that the virus tends to mutate overtime which makes it unrecognizable to the immune system.
<h3>Why is it difficult to get immunity to influenza?</h3>
Influenza is caused by a virus which tends to mutate overtime in order to stay ahead of medical technology.
As a result, this mutation makes the original virus unrecognizable to the immune system which would then be unable to fight it.
Find out more on natural immunity at brainly.com/question/21480961
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It is the ipomoea quamoclit flower.
Workers can protect themselves from accidents or being harmed when they are working on or near any construction zone by wearing high visibility reflective clothing in order to be easily seen by any moving machine operator. Directing traffic in construction zone, and walking quickly does not guarantee a safe working environment.
One is the Himalayas,qinling,yuh range,yin mountains,Lang mountains and that’s all I remember hope that helps :)