Prevents bacteria from entering the blood
<span>Edward Jenner discovered a vaccination against [smallpox] by infecting a boy with [cowpox]. He noticed that milkmaids who got cowpox never got smallpox and developed his theory from there. He is the father of the study of immunity and immunisation.</span>
It means you probably have a lack of vitamins consumed. You might wanna try eating healthier and eating items from the food pyramid to balance out your diet.
False, crossover designs are not most useful when the underlying intensity of disease has substantial within-person variability, such as larger seasonal changes.
<h3>When is crossover designs most useful?</h3>
A crossover design is a repeated measurements design such that each experimental unit receives different treatments during the different time periods.
That is the patients cross over from one treatment to another during the course of the trial.
Thus, crossover designs are not most useful when the underlying intensity of disease has substantial within-person variability, such as larger seasonal changes.
Learn more about crossover designs here: brainly.com/question/28039233
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