Vaccines don't provide immunity from disease for some people. but if most people get vaccinated against a disease, such as measles, then the population achieves "herd immunity," which means that there are so few cases of the disease that even people for whom vaccinations are ineffective are unlikely to contract the disease. an article in the economist magazine argues that, "herd immunity is a classic public good."

this statement is
a. not true, because not everyone can consume herd immunity whether or not they pay for it.
b. true, because immunity is nonexcludable, and everyone can simultaneously enjoy the? "herd immunity."
c. true, because a person receives some immunity from the disease by being vaccinated, even if other people are not vaccinated.
d. not true, because immunity is nonexcludable, but in order for it to occur there must be a herd, and there is no guarantee that enough people will get vaccinated.

B. true, because immunity is nonexcludable, and everyone can simultaneously enjoy the "herd immunity."

Explanation:

When a lot of people get vaccinated against a disease, the chances of spreading of that disease drastically decreases in the population. Even if someone is not vaccinated against that disease, their chances of contracting it are low because other people are vaccinated and hence its incidence rate in population is low. This phenomena is called as herd immunity. For example: 19 out of 20 people should be vaccinated against measles to protect the non vaccinated ones.

Herd immunity benefits the entire public and is considered a classic public good. It is nonexcludable which means that someone can not be excluded from being benefited by it. Two people residing in the same population will reap the benefits of herd immunity even if the degree of benefit might be different.

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.